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DAinAZ
08-07-2013, 02:28 PM
1992 ProStar 190, Ford 351 Indmar, 1:1

Finally decided to get the boat running again. Used it once in the last 3 years. (I know, I know. What am I thinking!) Has always run perfectly in the past.

Did all the beginning of season maintenance just to be sure, since I have been located in VA for the last 3 years, instead of AZ where we were for the first 16 years of the boats life. Changed the oil, water separator, spark plugs, checked the impeller (perfect). Then had to get my old dealer to send me one of each key (A,B,C & D) because we lost the key to the boat and the face of the ignition hole is not stamped, or has rubbed off.

Started up the boat and it started to overheat. Check the thermostat, and it was old and not working. Replaced that and started it up again. The boat ran perfectly at temperature. No issues on land. This was all done with a hose connected in line between the external pickup and the raw water impeller. (This adapter was installed at the dealer 20 years ago.)

Took it out on the lake and it ran pretty good. A little carburetor problems that I need to adjust (or probably clean and/or rebuild), but still able to take the boys around the lake behind the boat.

Whenever I would stop and shut off the boat, it seemed that the engine would overheat. The only way I knew, was that after a few minutes of sitting with the boat off, (changing out skier), when I would turn the boat back on, the temperature gage would go way up and the alarm would sound for a couple seconds. Then once the engine was running for about 15 seconds, the temperature would pull right back down to where it should be and run fine.

I don't know too much about the engine and system, but willing to get my hands dirty. Could it be something with the manifold? I saw a couple threads about the manifold being clogged on the sides. I've never had anything like that off my boat, so I've never looked inside.

It runs fine when the engine is running, and therefore the raw water pump is pulling in water. But after the engine is turned off, it seems to be overheating and don't know why.

Any help or opinions would be greatly appreciated. Sorry for the length of this post. Just wanted to make sure I gave enough background info.

mikeg205
08-07-2013, 02:30 PM
It's possible the water channels in the risers and exhaust manifolds have clogged - was it stored with the water plugs open?

DAinAZ
08-07-2013, 02:36 PM
It's possible the water channels in the risers and exhaust manifolds have clogged - was it stored with the water plugs open?

No. In AZ I never had to winterize, so I messed up and didn't winterize here. I know now that I need to, but I had it in a garage for the first 2 winters. Last winter it sat outside.

Being a newbie I'm not sure what the water plugs are. I did notice when I opened it up this year, that one of the black caps on the side of the manifold was off. I picked it up and tapped it back into place. I guess I should have looked at that point inside the hole, but didn't think about it then.

mikeg205
08-07-2013, 02:40 PM
I would check all of them - they also need RTV when they are placed back in... I would inspect the block carefully. Also the plugs I mean are in the rear of the exhaust manifolds and on the sides of block. If you never drained - the water jacked may be plugged up.

DAinAZ
08-07-2013, 02:49 PM
I'll put some RTV on the cap that came off, if I can get it off again. It seemed to fit pretty tight and snug when I tapped it back in.

Any possibility of getting a photo of where the plugs are on the sides of the block? I'll check the plugs on the exhaust manifold. Any thing in particular that I should be looking for when I take out the plugs? What should I expect?

thatsmrmastercraft
08-07-2013, 02:49 PM
My bet is a worn impeller not flowing enough water at idle, but the boat movement is providing adequate water flow.

mikeg205
08-07-2013, 02:52 PM
I don't have a Ford engine but look for brass fittings.

DAinAZ
08-07-2013, 03:29 PM
My bet is a worn impeller not flowing enough water at idle, but the boat movement is providing adequate water flow.

Impeller is perfect. Soft and flexible with no nicks, cuts or tears. It keeps perfect temp when it is idling. It is only AFTER the engine is shut off that it starts to heat up. Makes me think there is a leak somewhere that air is getting in allowing the water to flow out of the system. Maybe?

DAinAZ
08-07-2013, 03:30 PM
I don't have a Ford engine but look for brass fittings.

I checked some other threads for winterizing and was able to see some pics of the plugs on the manifolds. I assume the ones on the block look similar in configuration.

thatsmrmastercraft
08-07-2013, 03:42 PM
No. In AZ I never had to winterize, so I messed up and didn't winterize here. I know now that I need to, but I had it in a garage for the first 2 winters. Last winter it sat outside.

Being a newbie I'm not sure what the water plugs are. I did notice when I opened it up this year, that one of the black caps on the side of the manifold was off. I picked it up and tapped it back into place. I guess I should have looked at that point inside the hole, but didn't think about it then.

If a frost plug popped out, you may be dealing with a cracked block. Did it look something like this?

http://www.ford-trucks.com/user_gallery/sizeimage.php?photoid=148327&.jpg=

DAinAZ
08-07-2013, 03:47 PM
It looks like that plug is in the block in your picture. The plugs in my block are all good.

The plug (looks more like a flat cap) that popped out was on the side of the exhaust manifold. There are two on each manifold, but only one popped out.

thatsmrmastercraft
08-07-2013, 03:52 PM
It looks like that plug is in the block in your picture. The plugs in my block are all good.

The plug (looks more like a flat cap) that popped out was on the side of the exhaust manifold. There are two on each manifold, but only one popped out.

They serve the same purpose as casting plugs, but I think they are more prone to falling out by themselves on the exhaust manifolds.

thatsmrmastercraft
08-07-2013, 03:55 PM
When restarting after a skier change, and it starts running hot, is it difficult to start? Is it possible that your distributor advance is not returning all the way? If that were the case, it would run hot at idle with all the advance.

DAinAZ
08-07-2013, 04:01 PM
It starts pretty easy after a skier change. Once it starts, it only takes 10-15 seconds for it to cool down to running temperature, and that is while still at idle, before it has even been shifted into gear.

I am going to check the cap and rotor tonight just to see if that may be causing some of my stuttering issues that happens occasionally. I'll check the spring then too.

EDIT: Heading home from work now, so I will see what I can find. Won't post for a couple hours until I get my home chores done. Have to keep the family (wife) happy!

thatsmrmastercraft
08-07-2013, 04:04 PM
It starts pretty easy after a skier change. Once it starts, it only takes 10-15 seconds for it to cool down to running temperature, and that is while still at idle, before it has even been shifted into gear.

I am going to check the cap and rotor tonight just to see if that may be causing some of my stuttering issues that happens occasionally. I'll check the spring then too.

I have done the dance with sticking advance before and it can be a fun one if it doesn't happen every time. You might try running your blower at low speeds and opening your engine cover when stopped to try to isolate the source.

ahhudgins
08-07-2013, 04:18 PM
What is the actual temperature reading on your gauge when the boat is at idle?

Kevin 89MC
08-07-2013, 04:44 PM
What temp t-stat did you put in? There are 2 commonly available, ~140 or ~160 degree. I put the 160 in a few years ago, had the same problem as you. Switched to the 140 and now it almost never does it. The only time it does it now is after a barefoot or WOT run, if we shut down then start back up. The "high temp" alarm will sound for a few seconds, then shut off. I chalk it up to a little heat soak and don't worry about it too much. These engines run much hotter in vehicles, so I don't think a few seconds of "hi temp" will hurt much. I think mine might hit 210 or 220, pretty mild with respect to vehicle engine temps. Now that Peter mentioned it, I should check my distributor springs as well...

ahhudgins
08-07-2013, 05:15 PM
What temp t-stat did you put in? There are 2 commonly available, ~140 or ~160 degree. I put the 160 in a few years ago, had the same problem as you. Switched to the 140 and now it almost never does it. The only time it does it now is after a barefoot or WOT run, if we shut down then start back up. The "high temp" alarm will sound for a few seconds, then shut off. I chalk it up to a little heat soak and don't worry about it too much. These engines run much hotter in vehicles, so I don't think a few seconds of "hi temp" will hurt much. I think mine might hit 210 or 220, pretty mild with respect to vehicle engine temps. Now that Peter mentioned it, I should check my distributor springs as well...

That is why I'm waiting to see if he knows the actual temperature reading at idle. He might already be on the high side (above 160) due to a small cooling issue. 15 to 20 degrees of heat soak is normal which might put him over the limit.

thatsmrmastercraft
08-07-2013, 05:16 PM
That is why I'm waiting to see if he knows the actual temperature reading at idle. He might already be on the high side (above 160) due to a small cooling issue. 15 to 20 degrees of heat soak is normal which might put him over the limit.

Good point.

thatsmrmastercraft
08-07-2013, 05:17 PM
DAinAZ...have you checked the screen at the trans filter for debris?

DAinAZ
08-07-2013, 06:54 PM
I know it is a 142 thermostat because I checked the old one and new one before I installed it.

When idling and running the temp indicator is straight up. Not sure of the temp but that is what it has always been. (Ill check at home but I am out getting pizza now.)

I did take some pics of things. The dealer stuck in drains in the block, but not manifold. I was able to unscrew a manifold plug and check inside. Overall it looks clean. There was some rust debris I could feel with my finger at the bottom inside but not much.

99066
http://img.tapatalk.com/d/13/08/08/arequ4eb.jpg
http://img.tapatalk.com/d/13/08/08/uhe9a2at.jpg
http://img.tapatalk.com/d/13/08/08/qymepeta.jpg
http://img.tapatalk.com/d/13/08/08/6abese6e.jpg
http://img.tapatalk.com/d/13/08/08/ju2uvy5y.jpg

DAinAZ
08-07-2013, 06:58 PM
DAinAZ...have you checked the screen at the trans filter for debris?

I checked the water filter just inside from the intake. Is that what you are talking about?

DAinAZ
08-07-2013, 07:03 PM
I don't want to hijack my own thread, but in all my reading today I saw something about how the spark plug wires are arranged and that it could cause some stuttering when running.

Below are some pictures of my plug wires all bundled together. Also a picture of my cap. It doesn't look too worn in my opinion but wanted another look.
99068
99069
99070

thatsmrmastercraft
08-07-2013, 07:22 PM
I checked the water filter just inside from the intake. Is that what you are talking about?

Nope. The trans cooler where the water intake come from the bottom of the boat.

DAinAZ
08-07-2013, 07:23 PM
The normal temperature it runs at is 160. Is that hot for having a 142 thermostat in the boat? If I remember right it has always run at that temperature, but I may be wrong.
99073

thatsmrmastercraft
08-07-2013, 07:24 PM
I don't want to hijack my own thread, but in all my reading today I saw something about how the spark plug wires are arranged and that it could cause some stuttering when running.

Below are some pictures of my plug wires all bundled together. Also a picture of my cap. It doesn't look too worn in my opinion but wanted another look.
99068
99069
99070

Use a flat blade screwdriver to scrape the build-up off the contacts of the cap and rotor.

Never had a problem with cross-fire and I have had ford engines for a long time.

Traxx822
08-07-2013, 07:26 PM
You can't hijack your own thread. I have been watching it as I had the same issue.

Here is what was happening to me. Engine runs cool and perfect temp. At idle and at cruise speed. BUT!!! If I shut it off and let it sit for maybe 5-10 minutes when I turn the key back on the temp is spiked as the block heats up the water left in it. And some sensor somewhere would not let it fire up unless it was under 160. It would crank all day but not fire up until that needle was below 160

I spoke to my mechanic about it and he said he would look into it.

The next day he told me he disconnected some sensor and I shouldn't have anymore issues. now after sitting for 10 minutes it is pegged at 220 and after about 90 seconds of running it's back at 140 or less.

If what I described is what you are experiencing let me know and I'll ask my mechanic to be more specific.

I can attest it is very annoying to have to wait for your block to cool off before it will fire up.
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DAinAZ
08-07-2013, 08:02 PM
I just ran it and it is 150.


99076

The trans cooler is clean. Took off the hoses and looked inside.

It did look like more water was coming out the passenger side exhaust than the driver side exhaust. I could touch the passenger manifold and the riser was warmer, but could still put my hand on it. The driver side manifold was hotter. I could put my hand on the manifold but the riser I could only touch for a couple seconds.

In my previous post I said that I checked in the passenger manifold, but didn't look in the driver side manifold. Maybe the manifold and/or riser are clogged?

DAinAZ
08-07-2013, 08:07 PM
Here is what was happening to me. Engine runs cool and perfect temp. At idle and at cruise speed. BUT!!! If I shut it off and let it sit for maybe 5-10 minutes when I turn the key back on the temp is spiked as the block heats up the water left in it. And some sensor somewhere would not let it fire up unless it was under 160. It would crank all day but not fire up until that needle was below 160

I spoke to my mechanic about it and he said he would look into it.

The next day he told me he disconnected some sensor and I shouldn't have anymore issues. now after sitting for 10 minutes it is pegged at 220 and after about 90 seconds of running it's back at 140 or less.



That is exactly what is happening to me. It may be because my boat is a 1992, but it still starts when the gauge is pegged up at 220. It cools down probably within 10-15 seconds.

I don't think disconnecting a sensor is a fix, but that may be the sensor keeping your boat from starting. I would like to know why it is doing this at all. It hasn't done this for the first 15+ years. Why now? (Probably because it has been sitting.). But I would like to know specifically so it can be fixed.

ahhudgins
08-07-2013, 08:24 PM
You can't hijack your own thread. I have been watching it as I had the same issue.

Here is what was happening to me. Engine runs cool and perfect temp. At idle and at cruise speed. BUT!!! If I shut it off and let it sit for maybe 5-10 minutes when I turn the key back on the temp is spiked as the block heats up the water left in it. And some sensor somewhere would not let it fire up unless it was under 160. It would crank all day but not fire up until that needle was below 160

I spoke to my mechanic about it and he said he would look into it.

The next day he told me he disconnected some sensor and I shouldn't have anymore issues. now after sitting for 10 minutes it is pegged at 220 and after about 90 seconds of running it's back at 140 or less.

If what I described is what you are experiencing let me know and I'll ask my mechanic to be more specific.

I can attest it is very annoying to have to wait for your block to cool off before it will fire up.
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I have the exact same boat. Should be a 142 degree thermostat installed. There are 3 sensors related to temperature. One is the gauge, second is the warning light, third is the for the ECM. The only sensor he could have disconnected that would allow it to start is for the ECM, which will make the it think the engine is running cold all of the time and cause it to run rich. My boat runs at exactly the temperature of the thermostat. I installed a 160 and the boat ran at 160. When I shut it off to change skiers I had the "no start" issue exactly as you described until the engine cooled down. Put the 142 degree stat back in and no problems. My engine runs a little rich but I believe it's due to a crappy spray pattern on my injectors.

Traxx822
08-07-2013, 08:28 PM
That is exactly what is happening to me. It may be because my boat is a 1992, but it still starts when the gauge is pegged up at 220. It cools down probably within 10-15 seconds.

I don't think disconnecting a sensor is a fix, but that may be the sensor keeping your boat from starting. I would like to know why it is doing this at all. It hasn't done this for the first 15+ years. Why now? (Probably because it has been sitting.). But I would like to know specifically so it can be fixed.

Well then the difference here I see is yours would still start connected. Where as mine would not start. Once it hit somewhere over 180-190 the engine would turn over but not start. Then I would test it to try cranking to see if it would start at 200-190-180 and so on. It would fire up running good instantly upon reaching 159. With some part of the sensor disconnected (my gauge and warning lights on dash still work) now it will fire up at any temperature and cool off really fast just like yours does.

I know disconnecting isn't a solution and your right. Clearly yours starts no matter the temp with it connected and I most likely need to replace this sensor now. I bet it cuts off the engine in case of overheat risk and is bad. Disconnecting the sensor probably just is a band aid.

As to your subject topic I thought this was causing you an issue like mine. and learned I now have two issues. Since you have owned yours for years and it didn't do it before.

Is there any chance that it did do this before and you just never noticed?

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ahhudgins
08-07-2013, 08:29 PM
That is exactly what is happening to me. It may be because my boat is a 1992, but it still starts when the gauge is pegged up at 220. It cools down probably within 10-15 seconds.

I don't think disconnecting a sensor is a fix, but that may be the sensor keeping your boat from starting. I would like to know why it is doing this at all. It hasn't done this for the first 15+ years. Why now? (Probably because it has been sitting.). But I would like to know specifically so it can be fixed.

Did you do your test sitting in the lake or hooked up to a hose? If you are having a cooling issue it would show up more sitting in the lake rather than having a hose pushing water thru the system. Pardon my lack of knowledge, but is yours a carb or TBI? I'm going to see how high my temp goes up when I shut mine down this weekend....if we don't get rained out again :mad:

Now I am thread jacking. Where you located at? I'm in Forest and ski at Leesville.

ahhudgins
08-07-2013, 08:41 PM
First thing to do would be check the actual temperature with an infra red gun to make sure you actually have an overheating problem. Could just be a simple issue of a faulty temperature sending unit. +200 degrees from 150 seems like a huge jump unless all of the water is draining from the block when it shuts off.


Traxx, check my post #30

Traxx822
08-07-2013, 09:07 PM
First thing to do would be check the actual temperature with an infra red gun to make sure you actually have an overheating problem. Could just be a simple issue of a faulty temperature sending unit. +200 degrees from 150 seems like a huge jump unless all of the water is draining from the block when it shuts off.


Traxx, check my post #30

Good info. Thanks, I would have missed your post. I just recently put a mercruiser 140 in there. About a month ago. So I guess that ecm sensor is the problem for me?

I have an IR gun in my garage and will bring it next time I'm out.

But if the gauge is reading high and is a separate sensor than the ecm sensor then they both can't be bad and reading the same thing can they. I know my gauge works.

So is this an actual issue where the water shouldn't get hot after shut off? It's not supposed to do that? I just chalked it up to got day, 88 water temp and engine cover closed.

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DAinAZ
08-07-2013, 09:12 PM
With my boat being a 1992 ProStar 190, I don't have an ECM or any lights on my dash. It has a Holley 4160 carburetor. I have had the carb rebuilt once when it sat for awhile right after we had kids, but it ran great after that.

The test I did was in the driveway with a hose hooked up. It didn't do the overheating thing in the driveway. It only did the overheating out on the lake.

When I did pull the plug on the manifold tonight, before I ran it, there was about a quart of water in there, so it isn't leaking out of that one manifold. I did open both of the drains on the block and there was water in both sides of the block too. The only spot I didn't check was the driver side manifold plug.

I'm going to try and get it out to the lake on Saturday. I'll do some checking and testing then. I may get the manifold and riser gaskets so I can pull them to check those soon. But I don't think they are clogged from looking in the one.

Looking on other threads today, I'm wondering if one of the hoses may have "collapsed" inside causing a blockage. If I pull the risers, I might as well replace the hoses from the risers to the exhaust just to be sure.

Or maybe I just deal with it for the rest of this year and then make it an off-season project.

DAinAZ
08-07-2013, 09:18 PM
Where you located at? I'm in Forest and ski at Leesville.

I'm in Goochland, between Richmond and Charlottesville. Since I moved to VA from AZ in 2010, I used my boat once the first year, and it was in WV at Stonewall Jackson State Park (5.5 hours towing the boat through the WV mountains. It was for a family reunion, but none of us are from WV!). When I did my inaugural VA trip two weeks ago I went to Lake Anna. Takes me about 45 minutes door to door, and I glow at night now!

JimN
08-07-2013, 09:40 PM
You can't hijack your own thread. I have been watching it as I had the same issue.

Here is what was happening to me. Engine runs cool and perfect temp. At idle and at cruise speed. BUT!!! If I shut it off and let it sit for maybe 5-10 minutes when I turn the key back on the temp is spiked as the block heats up the water left in it. And some sensor somewhere would not let it fire up unless it was under 160. It would crank all day but not fire up until that needle was below 160

I spoke to my mechanic about it and he said he would look into it.

The next day he told me he disconnected some sensor and I shouldn't have anymore issues. now after sitting for 10 minutes it is pegged at 220 and after about 90 seconds of running it's back at 140 or less.

If what I described is what you are experiencing let me know and I'll ask my mechanic to be more specific.

I can attest it is very annoying to have to wait for your block to cool off before it will fire up.
Sent from my HTC One using Tapatalk 2

There is no sensor or code in the program that would keep an engine from starting if it was more than 160 degrees. 160 degrees is normal operating temperature. Overheat is registered when the ECT's resistance drops so it corresponds to about 210 degrees and even then, it will start, but it won't be pretty- RPM reduction will keep it from going over 2000 RPM. If you can't start it at all, open the throttle and see if it will. If that works, check the resistance of the ECT, especially if the exhaust smells strongly of unburned gas.

You can prevent most heat soak problems by idling for a few minutes after a hard run, rather than shutting it down immediately. You can also open the engine cover to let it cool faster. If you were seeing 160 on the temperature gauge, you need to know that the ECM gets temperature data from a completely different sensor, which has nothing to do with the gauge.

Traxx822
08-07-2013, 09:53 PM
There is no sensor or code in the program that would keep an engine from starting if it was more than 160 degrees. 160 degrees is normal operating temperature. Overheat is registered when the ECT's resistance drops so it corresponds to about 210 degrees and even then, it will start, but it won't be pretty- RPM reduction will keep it from going over 2000 RPM. If you can't start it at all, open the throttle and see if it will. If that works, check the resistance of the ECT, especially if the exhaust smells strongly of unburned gas.

You can prevent most heat soak problems by idling for a few minutes after a hard run, rather than shutting it down immediately. You can also open the engine cover to let it cool faster. If you were seeing 160 on the temperature gauge, you need to know that the ECM gets temperature data from a completely different sensor, which has nothing to do with the gauge.

I guess I thread jacked ... Sorry. But I need this fixed. Jim, it would still start if the gauge was at around 180-190 and after about 200 I guess you are right. I don't know exactly what temperature it would trip it to not start is I am just saying based off the 5-8 times I had to deal with this before my mechanic disconnected what it is speculated to be the ecm. I noticed this always after our run down the river and stop, open hatch and fill ballast bags. As for when I mentioned 160 so we all aren't confused, was after the engine would not start, I had to drop anchor and wait for the temperature to drop down to below 160 before it would start up again. It would take about 20 minutes to cool off. The manifolds felt extremely hot to the touch. Once it dropped below the threshold mentioned, she would fire right up.

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Traxx822
08-07-2013, 09:59 PM
Oh and I will take your advice about idle after rundown, and I will have my mechanic test the ect. I would basically just need to replace this. So why test it I ask. Anyways, I am concerned as you may remember I recently blew a head gasket and replaced the head gasket and exhaust gasket on port side. Has been running great since then.

I'm not going to lie, it has been nice to not have to worry about shutting down and not being able to restart with it disconnected so I am certainly confused on all this and do not want anything bad to happen.

Again op sorry minor thread jack.

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JimN
08-07-2013, 10:21 PM
I guess I thread jacked ... Sorry. But I need this fixed. Jim, it would still start if the gauge was at around 180-190 and after about 200 I guess you are right. I don't know exactly what temperature it would trip it to not start is I am just saying based off the 5-8 times I had to deal with this before my mechanic disconnected what it is speculated to be the ecm. I noticed this always after our run down the river and stop, open hatch and fill ballast bags. As for when I mentioned 160 so we all aren't confused, was after the engine would not start, I had to drop anchor and wait for the temperature to drop down to below 160 before it would start up again. It would take about 20 minutes to cool off. The manifolds felt extremely hot to the touch. Once it dropped below the threshold mentioned, she would fire right up.

Sent from my HTC One using Tapatalk 2

When was the last time you cleaned out your oil cooler and checked the impeller?

DAinAZ
08-07-2013, 10:23 PM
Not really a thread jack. Same issue, just different generation of boat and motor controls. Either way, it is all good information.

JimN
08-07-2013, 10:34 PM
Not really a thread jack. Same issue, just different generation of boat and motor controls. Either way, it is all good information.

Overheats cause a lot of problems and their causes are the same, whether EFI or carb- lack of water flow. The mechanisms that determine what happens after are different, but the result is the same and severe overheating causes a lot of damage.

ahhudgins
08-07-2013, 10:34 PM
There is no sensor or code in the program that would keep an engine from starting if it was more than 160 degrees. 160 degrees is normal operating temperature. Overheat is registered when the ECT's resistance drops so it corresponds to about 210 degrees and even then, it will start, but it won't be pretty- RPM reduction will keep it from going over 2000 RPM. If you can't start it at all, open the throttle and see if it will. If that works, check the resistance of the ECT, especially if the exhaust smells strongly of unburned gas.

You can prevent most heat soak problems by idling for a few minutes after a hard run, rather than shutting it down immediately. You can also open the engine cover to let it cool faster. If you were seeing 160 on the temperature gauge, you need to know that the ECM gets temperature data from a completely different sensor, which has nothing to do with the gauge.

My former MC dealer (who I trusted) no longer sells MC, and the new dealer knows more about pontoons than ski boats. I asked him why the 95 Maristar 200VRS uses the 142 degree thermostat and the 95 Prostars use the 160 with the same engines? His answer? Uhhhhhh?
I’ve verified these two subjects with other 200VRS owners on this board. If we install a 160 stat in our boats, they will not start back up after they sit for a few minutes. IIRC, When I was using the 160 degree stat, my temp would reach about 180 during heat soak and the engine would not restart until it cooled back down (don’t remember the exact temp). I changed the stats several times one weekend to make sure this was the issue…and it was. I kept the original 142 stat in the boat and there is never a restart problem. The other odd thing with the 200VRS is that we can’t rev the engine over about 2K in neutral. I contacted two other 200VRS owners and theirs did the same thing.
Don’t know why, they just won’t.:confused:

If we don’t get rained out this weekend I will try to do some temperature tests. According to my manual, the ECT is about 177 ohms at 212 degrees, so I will put a resistor in place of the ECT and she if she fires up.

ahhudgins
08-07-2013, 10:41 PM
Not really a thread jack. Same issue, just different generation of boat and motor controls. Either way, it is all good information.

Agreed. Since yours is a carb engine, you either have a faulty sensor for the gauge or an actual cooling issue. Just disconnect the alarm and the problem will go away!:D (Edit: I'm only kidding)

JimN
08-07-2013, 10:43 PM
My former MC dealer (who I trusted) no longer sells MC, and the new dealer knows more about pontoons than ski boats. I asked him why the 95 Maristar 200VRS uses the 142 degree thermostat and the 95 Prostars use the 160 with the same engines? His answer? Uhhhhhh?
Ive verified these two subjects with other 200VRS owners on this board. If we install a 160 stat in our boats, they will not start back up after they sit for a few minutes. IIRC, When I was using the 160 degree stat, my temp would reach about 180 during heat soak and the engine would not restart until it cooled back down (dont remember the exact temp). I changed the stats several times one weekend to make sure this was the issueand it was. I kept the original 142 stat in the boat and there is never a restart problem. The other odd thing with the 200VRS is that we cant rev the engine over about 2K in neutral. I contacted two other 200VRS owners and theirs did the same thing.
Dont know why, they just wont.:confused:

If we dont get rained out this weekend I will try to do some temperature tests. According to my manual, the ECT is about 177 ohms at 212 degrees, so I will put a resistor in place of the ECT and she if she fires up.

The quick answer for why they went to a 160 degree thermostat is that the newer controllers are better able to react to an overheat, they control everything better and because running at 142 wastes gas. Most cars use a 180-200 degree thermostat, but they also have a closed cooling system, so it's not as likely that the coolant will be absent, the way it can be if the impeller fails or the oil cooler is clogged. A warmer engine burns the fuel more completely and it needs less of it. Running an engine cold doesn't yield good performance, ever. It also increases the amount of gas that finds its way into the oil, causing premature engine wear/failure.

Try 500 Ohms- that's a happy temperature for the engine. If the engine won't rev past 2000 RPM, is it running rough? If so, it's toggling between the injectors to keep it from going past that, as an attempt to save the engine and reduce heat.

As I posted before, forget the gauge when it won't start- that has nothing to do with whether it will run, or not. However, I wouldn't recommend running it with a resistor in place of the ECT unless you're absolutely sure there's no problem with getting enough fresh water into the engine.

GoneBoatN
08-07-2013, 11:33 PM
1992 ProStar 190, Ford 351 Indmar, 1:1

Finally decided to get the boat running again. Used it once in the last 3 years. (I know, I know. What am I thinking!) Has always run perfectly in the past.

Did all the beginning of season maintenance just to be sure, since I have been located in VA for the last 3 years, instead of AZ where we were for the first 16 years of the boats life. Changed the oil, water separator, spark plugs, checked the impeller (perfect). Then had to get my old dealer to send me one of each key (A,B,C & D) because we lost the key to the boat and the face of the ignition hole is not stamped, or has rubbed off.

Started up the boat and it started to overheat. Check the thermostat, and it was old and not working. Replaced that and started it up again. The boat ran perfectly at temperature. No issues on land. This was all done with a hose connected in line between the external pickup and the raw water impeller. (This adapter was installed at the dealer 20 years ago.)

Took it out on the lake and it ran pretty good. A little carburetor problems that I need to adjust (or probably clean and/or rebuild), but still able to take the boys around the lake behind the boat.

Whenever I would stop and shut off the boat, it seemed that the engine would overheat. The only way I knew, was that after a few minutes of sitting with the boat off, (changing out skier), when I would turn the boat back on, the temperature gage would go way up and the alarm would sound for a couple seconds. Then once the engine was running for about 15 seconds, the temperature would pull right back down to where it should be and run fine.

I don't know too much about the engine and system, but willing to get my hands dirty. Could it be something with the manifold? I saw a couple threads about the manifold being clogged on the sides. I've never had anything like that off my boat, so I've never looked inside.

It runs fine when the engine is running, and therefore the raw water pump is pulling in water. But after the engine is turned off, it seems to be overheating and don't know why.

Any help or opinions would be greatly appreciated. Sorry for the length of this post. Just wanted to make sure I gave enough background info.

With my boat being a 1992 ProStar 190, I don't have an ECM or any lights on my dash. It has a Holley 4160 carburetor. I have had the carb rebuilt once when it sat for awhile right after we had kids, but it ran great after that.

The test I did was in the driveway with a hose hooked up. It didn't do the overheating thing in the driveway. It only did the overheating out on the lake.

When I did pull the plug on the manifold tonight, before I ran it, there was about a quart of water in there, so it isn't leaking out of that one manifold. I did open both of the drains on the block and there was water in both sides of the block too. The only spot I didn't check was the driver side manifold plug.

I'm going to try and get it out to the lake on Saturday. I'll do some checking and testing then. I may get the manifold and riser gaskets so I can pull them to check those soon. But I don't think they are clogged from looking in the one.

Looking on other threads today, I'm wondering if one of the hoses may have "collapsed" inside causing a blockage. If I pull the risers, I might as well replace the hoses from the risers to the exhaust just to be sure.

Or maybe I just deal with it for the rest of this year and then make it an off-season project.


So "checked the impeller" not "replaced the impeller". It's been sitting in there for 3 years summer-winter... Although it may "look good" my guess is that it most likely has taken a pretty good set - the vanes are bent over in one direction? This could be making the impeller less efficient. Perhaps the reason it does not do it in the driveway with host connected is that the hose pressure is providing a little extra water flow. If it were me I would invest $40 in the impeller. Disclaimer: just my thoughts... shoot me at will... ;)

GoneBoatN
08-07-2013, 11:59 PM
Traxx822, does this apply to you:

SERVICE ALERT
Date: April 26, 2001
Advisory #SA2001-2
SUBJECT: TBI Hard Start When Hot
Under certain conditions, customers may experience a hard start when hot situation with their
Throttle Body Fuel Injected (TBI) engines. These engines are equipped with the CEFI 3
Electronic Control Module (ECM). Generally, the engine will be able to start after opening the
throttle slightly and cranking the engine with the starter.
A calibration refinement has been made to remedy this hard start when hot condition. This
refined calibration went into production in November 2000, starting with engine serial number
IC977546. Any engines with serial number IC977546 or higher will already have this
calibration refinement. This calibration opens the Idle Air Control Valve slightly during
cranking, which allows sufficient air to pass through the system to allow an easier start.
If you have a hard start when hot complaint from a customer, the new calibration can be
downloaded into the CEFI 3 controller. If you have the WinCal recalibration software and
cable at your dealership, contact Indmar and we will send you the updated TBI calibration.
The calibration is identified with KKSUM 13885, Engine ID 12, Prom ID 14604.
If you do not have the WinCal software, you can remove the ECM from the boat and send it
to Indmar for recalibration. We will recalibrate the ECM the same day we receive it and return
it to you via the same means used to ship it to us. Send the ECM to:
Indmar
ECM Recalibration Services
5400 Old Millington Rd.
Millington, TN 38053
Make sure to tag the ECM with your dealership name and the serial number of the engine
when you send the ECM in for recalibration.

Traxx822
08-08-2013, 12:10 AM
When was the last time you cleaned out your oil cooler and checked the impeller?

Sorry for the delay, was watching oblivion.

I have never cleaned out my oil cooler. I replaced the impeller over last winter.

Sent from my HTC One using Tapatalk 2

Traxx822
08-08-2013, 12:16 AM
Traxx822, does this apply to you:

SERVICE ALERT
Date: April 26, 2001
Advisory #SA2001-2
SUBJECT: TBI Hard Start When Hot
Under certain conditions, customers may experience a hard start when hot situation with their
Throttle Body Fuel Injected (TBI) engines. These engines are equipped with the CEFI 3
Electronic Control Module (ECM). Generally, the engine will be able to start after opening the
throttle slightly and cranking the engine with the starter.
A calibration refinement has been made to remedy this hard start when hot condition. This
refined calibration went into production in November 2000, starting with engine serial number
IC977546. Any engines with serial number IC977546 or higher will already have this
calibration refinement. This calibration opens the Idle Air Control Valve slightly during
cranking, which allows sufficient air to pass through the system to allow an easier start.
If you have a hard start when hot complaint from a customer, the new calibration can be
downloaded into the CEFI 3 controller. If you have the WinCal recalibration software and
cable at your dealership, contact Indmar and we will send you the updated TBI calibration.
The calibration is identified with KKSUM 13885, Engine ID 12, Prom ID 14604.
If you do not have the WinCal software, you can remove the ECM from the boat and send it
to Indmar for recalibration. We will recalibrate the ECM the same day we receive it and return
it to you via the same means used to ship it to us. Send the ECM to:
Indmar
ECM Recalibration Services
5400 Old Millington Rd.
Millington, TN 38053
Make sure to tag the ECM with your dealership name and the serial number of the engine
when you send the ECM in for recalibration.

It sounds like it might. Is there a way to check? I guess, should I call Indmar or something and ask.

I will be having a sit down with my mechanic to find the solution.

I do not want this causing an issue with this motor. If I have to replace a motor I would have to sell my sled. That is out of the question.

Sent from my HTC One using Tapatalk 2

mikeg205
08-08-2013, 01:39 AM
Traxxx we have the same engine - I wonder if the t-stat is good. I had the same issue as hudgins when I tried a 160 t-stat...slow start when changing skiers. Went back to 142 everything is fine now.. let's not forget our river is in the high 80's now...

The temp sensor may be dirty or faulty - I like the idea of the IR gun to check real temp.

DAinAZ
08-08-2013, 07:24 AM
So "checked the impeller" not "replaced the impeller". It's been sitting in there for 3 years summer-winter... Although it may "look good" my guess is that it most likely has taken a pretty good set - the vanes are bent over in one direction? This could be making the impeller less efficient. Perhaps the reason it does not do it in the driveway with host connected is that the hose pressure is providing a little extra water flow. If it were me I would invest $40 in the impeller. Disclaimer: just my thoughts... shoot me at will... ;)

I believe I replaced the impeller 2 years ago when I used it in WV. I pulled it out last week and the vanes were flexible and looked good. I even had a new impeller in hand anticipating having to replace it. For 5 minutes work, I can put the new impeller in there this weekend and see if that helps. I can always keep the old impeller as my backup.

Something else to try. Thanks for the idea.

JimN
08-08-2013, 07:30 AM
Traxx822, does this apply to you:

SERVICE ALERT
Date: April 26, 2001
Advisory #SA2001-2
SUBJECT: TBI Hard Start When Hot
Under certain conditions, customers may experience a hard start when hot situation with their
Throttle Body Fuel Injected (TBI) engines. These engines are equipped with the CEFI 3
Electronic Control Module (ECM). Generally, the engine will be able to start after opening the
throttle slightly and cranking the engine with the starter.
A calibration refinement has been made to remedy this hard start when hot condition. This
refined calibration went into production in November 2000, starting with engine serial number
IC977546. Any engines with serial number IC977546 or higher will already have this
calibration refinement. This calibration opens the Idle Air Control Valve slightly during
cranking, which allows sufficient air to pass through the system to allow an easier start.
If you have a hard start when hot complaint from a customer, the new calibration can be
downloaded into the CEFI 3 controller. If you have the WinCal recalibration software and
cable at your dealership, contact Indmar and we will send you the updated TBI calibration.
The calibration is identified with KKSUM 13885, Engine ID 12, Prom ID 14604.
If you do not have the WinCal software, you can remove the ECM from the boat and send it
to Indmar for recalibration. We will recalibrate the ECM the same day we receive it and return
it to you via the same means used to ship it to us. Send the ECM to:
Indmar
ECM Recalibration Services
5400 Old Millington Rd.
Millington, TN 38053
Make sure to tag the ECM with your dealership name and the serial number of the engine
when you send the ECM in for recalibration.

That's the recal I have referred to in the past- Alan's shop had finished the testing and validation and while MC was getting ready for production, Rochester decided to omit the hole in the throttle plate without telling anyone, which wasn't a problem when cold but caused overly rich mixture/hard restart when hot. The recal causes the IAC to open more during repark after the key is turned off.

If the boat is an '01 and never had this problem before now, it probably doesn't need this recalibration but it wouldn't hurt to contact MC to ask if they have a warranty claim for this boat/engine. If it wasn't done, it's because the dealer didn't do it, for some reason. If this boat was owned by someone else at the time, they may not have bothered or they may have used it where a dealer wasn't close enough. There's no good excuse for not doing it, though.

JimN
08-08-2013, 07:33 AM
I believe I replaced the impeller 2 years ago when I used it in WV. I pulled it out last week and the vanes were flexible and looked good. I even had a new impeller in hand anticipating having to replace it. For 5 minutes work, I can put the new impeller in there this weekend and see if that helps. I can always keep the old impeller as my backup.

Something else to try. Thanks for the idea.

How flexible? If you place the impeller in a table and the vanes move visibly from its weight, toss it. It's not able to supply enough water now and it won't work as a backup. Replace the gasket, too. These can't be successfully re-used.

Traxx822
08-08-2013, 08:13 AM
Traxxx we have the same engine - I wonder if the t-stat is good. I had the same issue as hudgins when I tried a 160 t-stat...slow start when changing skiers. Went back to 142 everything is fine now.. let's not forget our river is in the high 80's now...

The temp sensor may be dirty or faulty - I like the idea of the IR gun to check real temp.

T stat is new. Check post 34

Sent from my HTC One using Tapatalk 2

bcd
08-08-2013, 08:33 AM
What confuses me is how far it shoots up after shutting the engine off. Once the engine is off, no more heat is getting added to the system. They only way the water will continue to be heated up is by a heat imbalance somewhere in the engine, for example, you have plenty of cooling water flowing through the engine near where the temp sensor and thermostat are, so everything reads fine when running, but little to no cooling somewhere else. Once the cooling water flow stops, heat transfer inside the engine continues until the engine temperature is relatively equal. What concerns me is that you heat the water from 160 all the way past 220, which means whatever is doing the engine off heating is well over 220. If you get the laser temp reader, shoot the whole engine to see if you can find any hot spots. Otherwise, maybe you can feel around the engine to see if you notice any hotspots.

DAinAZ
08-08-2013, 08:40 AM
How flexible? If you place the impeller in a table and the vanes move visibly from its weight, toss it. It's not able to supply enough water now and it won't work as a backup. Replace the gasket, too. These can't be successfully re-used.

Not that flexible. They would bend when I would push them with my fingers, but not flex by the weight of the impeller itself. I was trying to explain that they weren't dry rotted and cracking if they were flexed.

Good point though. In AZ the issue was always dry rot. They would just crack and fall apart. Now that I am in a more humid area, that probably isn't as big of an issue.

DAinAZ
08-08-2013, 08:43 AM
What confuses me is how far it shoots up after shutting the engine off. Once the engine is off, no more heat is getting added to the system. They only way the water will continue to be heated up is by a heat imbalance somewhere in the engine, for example, you have plenty of cooling water flowing through the engine near where the temp sensor and thermostat are, so everything reads fine when running, but little to no cooling somewhere else. Once the cooling water flow stops, heat transfer inside the engine continues until the engine temperature is relatively equal. What concerns me is that you heat the water from 160 all the way past 220, which means whatever is doing the engine off heating is well over 220. If you get the laser temp reader, shoot the whole engine to see if you can find any hot spots. Otherwise, maybe you can feel around the engine to see if you notice any hotspots.

Basic thermodynamics. I haven't really put two and two together, but if it is actually heating up that much that fast, there is some serious heat buildup somewhere else.

I need to find a temperature gun to check it this weekend. Any suggestions where to pick one up cheap (cheaper).

d2jp
08-08-2013, 09:12 AM
.........You can prevent most heat soak problems by idling for a few minutes after a hard run, rather than shutting it down immediately. You can also open the engine cover to let it cool faster. If you were seeing 160 on the temperature gauge, you need to know that the ECM gets temperature data from a completely different sensor, which has nothing to do with the gauge.

^^THIS^^ Is what I do - allow the engine to idle for a few minutes. If I shut it down right away, I will see a temp jump from 140ish to 180~200. Idle for just 30-60 seconds and it's fine. Whenever possible, I try to pick up my skier using the method I learned here...skier is down-pull throttle-idle boat- THEN make turn to retrieve-idle back to down skier-kill engine. This process allows the motor to cool rather than barreling back to skier and then shut down.

ahhudgins - Last year by now I had put 100 hours on my boat, this year....7 hours. Damn rain just won't stop.

mikeg205
08-08-2013, 09:25 AM
T stat is new. Check post 34

Sent from my HTC One using Tapatalk 2

Just cuz it's new don't mean it works correctly... sorry you're having issues with powerplant

swardco
08-08-2013, 12:45 PM
On my 91 Prostar 190, if you let the boat idle for even 30 seconds to a minute after pulling a set in the course, the temp stays nicely under control. If you immediately shut it down upon dropping a skier, I have seen the temperature be high on restart. This just makes sense to me that when the engine is running at temp you would want to have water running, so letting the water flow for a little bit after running hard just seemed like the correct thing to do.

Kweisner
08-08-2013, 01:15 PM
What confuses me is how far it shoots up after shutting the engine off. Once the engine is off, no more heat is getting added to the system.

The corollary of this is also that heat is no longer being subtracted from the system. Metal components are always going to be hotter than the water jacket. The water will only have a bit of time in which it's being warmed before it is expelled and replaced with fresh, cooler water. Upon stopping, the water is no longer flowing, and therefore has more time to get heated by the engine. Engine temp isn't really increasing, but "apparent" temp is because it's the water that's being measured. . . unless I'm way off the beam here.

I would agree that running on at idle for a half minute or so should alleviate this issue.

ahhudgins
08-08-2013, 04:07 PM
The corollary of this is also that heat is no longer being subtracted from the system. Metal components are always going to be hotter than the water jacket. The water will only have a bit of time in which it's being warmed before it is expelled and replaced with fresh, cooler water. Upon stopping, the water is no longer flowing, and therefore has more time to get heated by the engine. Engine temp isn't really increasing, but "apparent" temp is because it's the water that's being measured. . . unless I'm way off the beam here.

I would agree that running on at idle for a half minute or so should alleviate this issue.

I was just going to say "The water is gettin' hot cuz there ain't no more cold water going thru the engine":D

thatsmrmastercraft
08-08-2013, 04:09 PM
I was just going to say "The water is gettin' hot cuz there ain't no more cold water going thru the engine":D

:uglyhamme:uglyhamme:uglyhamme

DAinAZ
08-08-2013, 07:54 PM
I got a 1/2" ratchet and was able to take the plug off the manifold after work today. Again about a quart of water or more, along with some old impeller bits, along with some small rust pieces. The main thing I did notice is that when looking in the hole towards the engine, there is an internal wall there that looks solid. The other side had what looked like flash from the casting process, but was open. From looking at the one tonight, I have to believe that the wall is supposed to be there, and if the first one is rusted through inside, that may be part of the cause of the odd cooling habits. Below is a pic of the first manifold with the wall "missing".

99123

I made it large so you can see the detail inside.

DAinAZ
08-08-2013, 07:59 PM
So "checked the impeller" not "replaced the impeller". It's been sitting in there for 3 years summer-winter... Although it may "look good" my guess is that it most likely has taken a pretty good set - the vanes are bent over in one direction? This could be making the impeller less efficient. Perhaps the reason it does not do it in the driveway with host connected is that the hose pressure is providing a little extra water flow. If it were me I would invest $40 in the impeller. Disclaimer: just my thoughts... shoot me at will... ;)

I replaced the impeller for our hopeful lake trip this Saturday. The old impeller vanes were a bit warped, but not bad.

99124

DAinAZ
08-12-2013, 11:02 AM
Got out this Saturday and followed the advice to let the boat idle a bit before shutting off. Seemed to work and I only saw the temp gauge go up to about 180 once I turned it back on, and it went down to 150 or so within 10 seconds. Didn't overheat at all while running.

My bigger issue now is my carburetor. After idling for a while, it would want to die when I put it into gear to get the rope tight before starting. Luckily a friend was out on the lake with us with his fishing boat. Right when a storm came through and started dumping rain on us, we were getting pushed into shore and I couldn't get the boat started. He was able to pull us off the shore and out into the lake and hold us until I could get it started again.

So now my carb is my main focus. I was hoping to wait until the end of the season before having to dive into that project. Now I have risers/manifold for the off season and carb right now.

thatsmrmastercraft
08-12-2013, 11:08 AM
Could be as simple as needing to bump the idle speed up.......what speed was it idling at when it would die?

Is this a new issue or been going on for a while. Could be rebuild time. Ethanol may have been working it's magic. Likely you are dumping fuel at idle. Take a careful look down the carb throat to see what is going on.

Electronic ignition or points?

DAinAZ
08-12-2013, 11:25 AM
Could be as simple as needing to bump the idle speed up.......what speed was it idling at when it would die?

Is this a new issue or been going on for a while. Could be rebuild time. Ethanol may have been working it's magic. Likely you are dumping fuel at idle. Take a careful look down the carb throat to see what is going on.

Electronic ignition or points?

After pulling someone, it would idle fine. I think it is gummed up a bit from sitting too long and not having been "winterized" at the time. I looked in the carb when it was running and nothing looked unusual, and also right after shutoff. Didn't see anything happening.

It has been doing this since starting it up after not running it for about 2 years.

Points, not electronic ignition.

Never rebuilt a carb. How long should it take/how difficult for someone who is mechanically inclined but never done it before?

Traxx822
08-18-2013, 09:17 AM
I wanted to throw my update in here.

I replaced the ECT sensor and no more problem. Starts up at any temp now. Although I do watch for the heat soak still.

JimN
08-18-2013, 09:39 AM
I wanted to throw my update in here.

I replaced the ECT sensor and no more problem. Starts up at any temp now. Although I do watch for the heat soak still.

You can't stop heat soak- it's caused by heat being lost from the hottest areas of the engine to the cooler areas. However, you can reduce the extreme temperature swing by idling for about a minute after a hard run, to get the temperature down to a normal level. The in-cylinder temperatures can exceed 1000F when running hard.

Traxx822
08-18-2013, 09:47 AM
You can't stop heat soak- it's caused by heat being lost from the hottest areas of the engine to the cooler areas. However, you can reduce the extreme temperature swing by idling for about a minute after a hard run, to get the temperature down to a normal level. The in-cylinder temperatures can exceed 1000F when running hard.

Thank Jim, I now understand heat soak thanks to this thread. My problem was the bad sensor for some reason causing my boat not to start with heatsoak. I now idle the boat for a while and monitor the temp while oof. Sometimes just letting it sit and heat up a bit, and then restarting (therefor refreshing the water that got heated) makes it all go away.

But my earlier problem was it wouldn't allow me to start if it got above about 180, now it starts at any temperature.

The sensor was clearly bad, some of you guys suggested ohms etc and we tested it as recommended and it was way off. So I think that was my issue.

JimN
08-18-2013, 10:08 AM
Thank Jim, I now understand heat soak thanks to this thread. My problem was the bad sensor for some reason causing my boat not to start with heatsoak. I now idle the boat for a while and monitor the temp while oof. Sometimes just letting it sit and heat up a bit, and then restarting (therefor refreshing the water that got heated) makes it all go away.

But my earlier problem was it wouldn't allow me to start if it got above about 180, now it starts at any temperature.

The sensor was clearly bad, some of you guys suggested ohms etc and we tested it as recommended and it was way off. So I think that was my issue.

Low resistance, or if it's intermittent, will definitely cause this. You could also open the throttle a bit if this happens again when rich exhaust is the key- if it smells like gasoline and it's very hot, something is wrong. If it doesn't smell like gas, it usually indicates simple heat soak. The people who did the calibrations and setup in the past would go to Arizona in summer to test at the GM Desert Proving Ground so they could work in real-world situations and they ended up increasing the overheat trigger temperature on the LT-1 to over 200F. It's a safe temperature for short-term and it eliminated a lot of hot-start problems for people with this engine. Hot air and warm water make this far more of a problem than in cooler water and if the boat has run in warm, shallow water in the SW US or some other place, the water temperature could be 90F, which makes cooling a very slow process.

Good to see the problem is gone.

carlbernhard
08-19-2013, 04:09 PM
I believe I replaced the impeller 2 years ago when I used it in WV. I pulled it out last week and the vanes were flexible and looked good. I even had a new impeller in hand anticipating having to replace it. For 5 minutes work, I can put the new impeller in there this weekend and see if that helps. I can always keep the old impeller as my backup.

Something else to try. Thanks for the idea.
I had exactly the same problem on a 89 prostar. I had a welsh plug that had corroded through and leaky exhaust manifold gaskets. When i replaced the gaskets and the welsh plug the problem was better but not completely remedied. I would run through the entire cooling system as follows:
1.Check through hull pick up for debris
2. Check oil cooler for obstacles
3. check all pipes and hose clamps
4. Rebuild raw water pump ( or just replace impeller if bearings are fine and no leaks
5. Replace thermostat with correct t stat
6. Replace exhaust gaskets and riser manifold gaskets and check for corrosion
7. do a full compression test to identify potential head gasket damage

Replacement of the welsh plug and exhaust manifold gasket def improved the issue but did not completely solve it.
I have since pulled my engine apart for a complete rebuild ( due to a number of other unrelated issues ) and will post my findings after the entire system is running as new.
Good luck

JimN
08-19-2013, 04:21 PM
After pulling someone, it would idle fine. I think it is gummed up a bit from sitting too long and not having been "winterized" at the time. I looked in the carb when it was running and nothing looked unusual, and also right after shutoff. Didn't see anything happening.

It has been doing this since starting it up after not running it for about 2 years.

Points, not electronic ignition.

Never rebuilt a carb. How long should it take/how difficult for someone who is mechanically inclined but never done it before?

Did you replace the impeller? Anyplace that has high ambient temperatures, I would be extra meticulous about the impeller, specifically and the cooling system, generally. Your high air AND water temps makes it a formula for disaster if the impeller has become weak and in high heat, that happens a lot faster than in a more moderate climate. Out there, a one year old impeller can act like it's more than three y.o. in Wisconsin.

BrianE
09-09-2013, 10:56 AM
When was the last time you cleaned out your oil cooler and checked the impeller?

Thanks JimN for your constant guidance!... I noticed that my exhaust was steamy, exhaust manifold risers were hot and it didn't make sense as the impeller housing was cool. I replaced my impeller, but for whatever reason, I had thought my most recent check of my transmission cooler was more recent than actual. Sure enough, it was clogged up causing poor flow.

I have cleaned this out and have no more symptoms, but I am certain that I have run the boat for 22 hours without proper flow (what a jackass).

The boat is running well.
What other maintenance would you perform on the boat?
Oil change? Exhaust tube inspection?

Thanks again.

JimN
09-09-2013, 05:23 PM
Thanks JimN for your constant guidance!... I noticed that my exhaust was steamy, exhaust manifold risers were hot and it didn't make sense as the impeller housing was cool. I replaced my impeller, but for whatever reason, I had thought my most recent check of my transmission cooler was more recent than actual. Sure enough, it was clogged up causing poor flow.

I have cleaned this out and have no more symptoms, but I am certain that I have run the boat for 22 hours without proper flow (what a jackass).

The boat is running well.
What other maintenance would you perform on the boat?
Oil change? Exhaust tube inspection?

Thanks again.

If it was running hot, I would change the oil and filter because oil that has been exposed to temperature extremes loses some of its ability to lubricate and resistance to shear. These contribute to decrease the oil film, which is very important.I would squeeze the exhaust hoses to see if they have become soft and also look at the flappers to see if they have any damage. If they and the exhaust flanges aren't blistered, I would say that you dodged a bullet.

BrianE
09-17-2013, 11:22 PM
If it was running hot, I would change the oil and filter because oil that has been exposed to temperature extremes loses some of its ability to lubricate and resistance to shear. These contribute to decrease the oil film, which is very important.I would squeeze the exhaust hoses to see if they have become soft and also look at the flappers to see if they have any damage. If they and the exhaust flanges aren't blistered, I would say that you dodged a bullet.
Thank you!