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View Full Version : Boat dies at higher RPM's


SkiDog
04-08-2012, 08:46 PM
Took my boat out today. Ran great on the hose for about 30 minutes, so I decided to take it to
real water. First thing, was it was hard to start. Started right up on the hose, but once in the water, it took it a while to finally start. Back it off the trailer and idled out. Running fine, all gauges are looking good. Volt meter MAYBE a little suspect. It was running at about 12.5 volts. Running dual batteries and running on both batteries too. Get it up to about 2400 RPM's and after a few seconds it just completely dies. Back off the throttle and it stays running. Throttle up again, same thing. Runs great at 1900 and below, but not above. Anybody got ANY ideas? NOTE: I did not put any fuel additive in the tank at the end of last year, and I topped it off today, but it only held about 7 gallons.

Footin
04-08-2012, 09:02 PM
Fuel filters, points?

SkiDog
04-08-2012, 09:08 PM
Fuel filters, points?

Maybe! Idunno.

TOO-TALL
04-08-2012, 09:25 PM
Will the motor rev up over 1900 in neutral...no load on motor.

TOO-TALL
04-08-2012, 09:27 PM
Just reread your post...Maybe a stuck float bowl in the carb?

erkoehler
04-09-2012, 08:31 AM
Take the cap off and look inside, corrosion on connectors?

JimN
04-09-2012, 09:02 AM
Took my boat out today. Ran great on the hose for about 30 minutes, so I decided to take it to
real water. First thing, was it was hard to start. Started right up on the hose, but once in the water, it took it a while to finally start. Back it off the trailer and idled out. Running fine, all gauges are looking good. Volt meter MAYBE a little suspect. It was running at about 12.5 volts. Running dual batteries and running on both batteries too. Get it up to about 2400 RPM's and after a few seconds it just completely dies. Back off the throttle and it stays running. Throttle up again, same thing. Runs great at 1900 and below, but not above. Anybody got ANY ideas? NOTE: I did not put any fuel additive in the tank at the end of last year, and I topped it off today, but it only held about 7 gallons.

Could be bad gas/water in the bowl, clogged fuel filter (water molecules are larger than gas molecules, but the filter may not be fine enough to filter either out of the stream), dirty battery terminals,....

Is the boat a '92 Prostar, as it shows in your profile? MEASURE the voltage and compare that with the gauge- if it's lower at the batteries, charge them fully before trying to run it again. If you haven't replaced the fuel filter in a while (more than a year), I would replace that. Verify your timing- if you still have points, it changes over time and the wedge that rides on the distributor cam can wear down.

Have you cleaned/checked the flame arrestor, lately?

BallBushing
04-09-2012, 09:23 AM
Check the transmission cooler, if weeds are in there that will cause a problem like this. Happened to me last year.

SkiDog
04-09-2012, 02:55 PM
Could be bad gas/water in the bowl, clogged fuel filter (water molecules are larger than gas molecules, but the filter may not be fine enough to filter either out of the stream), dirty battery terminals,....

Is the boat a '92 Prostar, as it shows in your profile? MEASURE the voltage and compare that with the gauge- if it's lower at the batteries, charge them fully before trying to run it again. If you haven't replaced the fuel filter in a while (more than a year), I would replace that. Verify your timing- if you still have points, it changes over time and the wedge that rides on the distributor cam can wear down.

Have you cleaned/checked the flame arrestor, lately?

yea, Jim, 92 prostar. Going to change the fuel filter today. I believe that BOTH batteries were fully charged. I did that 2 weeks ago. I remember last year this happening one time. Had been running the stereo pretty much all day one one battery. Went to leave and it did this. Stopped, changed over to BOTH batteries and it was fine. didn't do it anymore. But I've had 5 people tell me that its either a clogged fuel filter or perhaps a bad fuel line from running flexfuel in it and its eaten the inside of the lines up. Ever heard of that?

east tx skier
04-09-2012, 03:09 PM
Wait. You're running E85 in your 92 MC?

CantRepeat
04-09-2012, 03:17 PM
Wait. You're running E85 in your 92 MC?

Yeah Flex Fuel or E85 is not the stuff to run, in anything non E85 rated, and if you have been running that in the boat then you could be some real trouble. More so if it sat in the boat all winter long.

The 10% stuff is bad enough but going to 85% ethanol is just really bad.

Or should I say, so I've read.

SkiDog
04-09-2012, 03:24 PM
Any tips on taking off the old filter? I've got a filter wrench, but it ain't doing the trick!:mad: Guess I could pull the motor to be able to get to it!

pram
04-09-2012, 03:30 PM
Is the water separation filter in the lower port side at the front?

SkiDog
04-09-2012, 03:34 PM
Is the water separation filter in the lower port side at the front?

Thats what I am changing. Its right below the fuel pump. Fram PS3808.

pram
04-09-2012, 03:37 PM
can you unbolt the water separator unhook the fuel lines and put it on a bench?

SkiDog
04-09-2012, 03:44 PM
can you unbolt the water separator unhook the fuel lines and put it on a bench?

Now there's an idea! Thanks pram! that'll give me a chance to look at the fuel line too!

pram
04-09-2012, 04:16 PM
Most Excellent

JimN
04-09-2012, 04:29 PM
yea, Jim, 92 prostar. Going to change the fuel filter today. I believe that BOTH batteries were fully charged. I did that 2 weeks ago. I remember last year this happening one time. Had been running the stereo pretty much all day one one battery. Went to leave and it did this. Stopped, changed over to BOTH batteries and it was fine. didn't do it anymore. But I've had 5 people tell me that its either a clogged fuel filter or perhaps a bad fuel line from running flexfuel in it and its eaten the inside of the lines up. Ever heard of that?

E85? What the?

FlexFuel isn't the fuel, it refers to the ability of the vehicle to be flexible in its fuel use. E85 isn't made for rubber fuel lines and if you read up on it, even new cars that aren't made to run on it WILL be damaged if it's used.

E10 is bad enough in cars because the alcohol decreases the energy/unit significantly but the only reason E85 is better than pure ethanol is because it has some gas in it. Methanol is even worse. Plus, alcohol is extremely corrosive to many materials and if you see black stuff in the filter, it's because your fuel lines were never made for this crap. This shyte will kill your carb, fuel lines (including the hard lines), seals, gaskets- it's bad news! I wouldn't run that stuff in my lawnmower. Any fuel with alcohol in it will attract water from the atmosphere if given the chance and a vented fuel tank guarantees this. A car or truck has a sealed, pressurized fuel system and because of this, the water in the air doesn't get to the fuel to the same degree.

Fuel Unit Btu/Unit Energy % of gasoline

gasoline gallon 116,090
diesel gallon 129,488
biodiesel gallon 119,550
ethanol gallon 76,330 66%
E85 gallon 82,000 70.6%
LPG gallon 84,950
methanol gallon 57,250 49.31%

east tx skier
04-09-2012, 04:33 PM
Any tips on taking off the old filter? I've got a filter wrench, but it ain't doing the trick!:mad: Guess I could pull the motor to be able to get to it!

Turn it the other way. No, I'm not being snarky. I made that mistake once. Alternatively, use two filter wrenches on it.

There should be two fuel filters. The spin on fuel/water seperator and the cartridge that goes in the housing at the base of the fuel pump. Be sure to change them both.

east tx skier
04-09-2012, 04:36 PM
Yeah Flex Fuel or E85 is not the stuff to run, in anything non E85 rated, and if you have been running that in the boat then you could be some real trouble. More so if it sat in the boat all winter long.

The 10% stuff is bad enough but going to 85% ethanol is just really bad.

Or should I say, so I've read.

I think we are getting to the root of the issue.

CantRepeat
04-09-2012, 04:43 PM
I'd suggest draining whatever you have left in there for sure. If you can't then I've read add as much 87 unleaded every chance you get.

Jerseydave
04-09-2012, 05:16 PM
I'd suggest draining whatever you have left in there for sure. If you can't then I've read add as much 87 unleaded every chance you get.

I think you mean add a higher octane gas (like 92-93 octane) to your old gas to bring up the octane rating to perhap 89 or so.

I agree with changing the fuel filter, drain or siphon out the old gas, make sure the batteries are fully charged and go from there. A bottle of dry gas added to some new non-ethanol 89 octane is what I would do.

east tx skier
04-09-2012, 05:18 PM
Whatever you do, you might want to get that "flex fuel" decal off the boat.

/I kid.

8p

SkiDog
04-09-2012, 05:34 PM
took Prams advice and unbolted the whole damn thing. Thanks PRAM! This is what I found! A little dirty. But after draining the gas, I really didn't see any foreign matter.. I cleaned it up and replaced with new Fram PS3808 filter. Did not change the one on the bottom of the pump yet.

CantRepeat
04-09-2012, 05:43 PM
I think you mean add a higher octane gas (like 92-93 octane) to your old gas to bring up the octane rating to perhap 89 or so.

I agree with changing the fuel filter, drain or siphon out the old gas, make sure the batteries are fully charged and go from there. A bottle of dry gas added to some new non-ethanol 89 octane is what I would do.

Nope that's not what I mean.

E85 has a pretty high octane rating already. It's higher then premium and normally around 94 to 96 rating.

I'd check the inside of the fuel lines while you have that off. You might even want to pull the float bowls off and check them out.

CantRepeat
04-09-2012, 05:47 PM
Whatever you do, you might want to get that "flex fuel" decal off the boat.

/I kid.

8p

Bad, Doug, bad!!!

CantRepeat
04-09-2012, 05:48 PM
I think you mean add a higher octane gas (like 92-93 octane) to your old gas to bring up the octane rating to perhap 89 or so.

I agree with changing the fuel filter, drain or siphon out the old gas, make sure the batteries are fully charged and go from there. A bottle of dry gas added to some new non-ethanol 89 octane is what I would do.

Also, I believe dry gas is nothing more then more alcohol which we know the gas does not need. In fact, that might just compound the issue.

east tx skier
04-09-2012, 05:53 PM
Drain the whole thing and pump some 89 octane in there. All that E85 probably reconstituted into a corn cob and is clogging up the fuel pickup.

SkiDog
04-09-2012, 05:55 PM
Drain the whole thing and pump some 89 octane in there. All that E85 probably reconstituted into a corn cob and is clogging up the fuel pickup.

I really hope you don't mean drain the WHOLE tank! Its FULL! Topped off yesterday.:confused::confused:

CantRepeat
04-09-2012, 05:58 PM
I really hope you don't mean drain the WHOLE tank! Its FULL! Topped off yesterday.:confused::confused:

Yup, all of it!

Well, tbh, one tank that was filled and ran out probably isn't that big a deal. It's the long term usage and storage of it in system that was not designed for it is the big issue.

If you drain, running 89 or 92 wont make any difference. You can keep going with just 87.

More importantly is to check the condition of the rubber fuel lines, the needle seats in the carb, and maybe the fuel pump.

I do agree that draining is the best solution.

pram
04-09-2012, 06:12 PM
I took the tank out of my 95 2 weeks ago and cleaned it up

SkiDog
04-09-2012, 06:12 PM
Yup, all of it!

Well, tbh, one tank that was filled and ran out probably isn't that big a deal. It's the long term usage and storage of it in system that was not designed for it is the big issue.

If you drain, running 89 or 92 wont make any difference. You can keep going with just 87.

More importantly is to check the condition of the rubber fuel lines, the needle seats in the carb, and maybe the fuel pump.

I do agree that draining is the best solution.

Ok, I assume that there's a filter in here too. Question is, How do I get this bottom part off? IF that's where the filter is.

pram
04-09-2012, 06:15 PM
as far as I know you only undue the bolt on the bottom and because water is heavier than gas anything in the bottom will drain out

but I have been wrong before and will be wrong again

pram
04-09-2012, 06:16 PM
and clean up that rust would yah :rolleyes:

it's despicable

Jerseydave
04-09-2012, 06:30 PM
Ok, I assume that there's a filter in here too. Question is, How do I get this bottom part off? IF that's where the filter is.

Unscrew the bolt on the bottom and the "clamp" that holds the bowl in place it will swing out of the way so you can remove the bowl and clean it. It's just like on a farm tractor, (usually those are clear glass) so you can see if dirt is getting trapped in there. There should be a gasket or o-ring at the top of that bowl so be careful with it so you can re-use it.

Table Rocker
04-09-2012, 06:39 PM
Question is, How do I get this bottom part off?Loosen the bolt on the bottom as far as it will go. Then you can lift the strap and move it from the upper notch and remove it. The sediment bowl will then just drop straight down. It is held in place by the bolt you loosened in step 1.

CantRepeat
04-09-2012, 06:46 PM
I don't think it swings out. You should just unscrew it the point where it will come out of the top bracket and then remove the bowl.

east tx skier
04-09-2012, 07:16 PM
Yup, all of it!

Well, tbh, one tank that was filled and ran out probably isn't that big a deal. It's the long term usage and storage of it in system that was not designed for it is the big issue.

If you drain, running 89 or 92 wont make any difference. You can keep going with just 87.

More importantly is to check the condition of the rubber fuel lines, the needle seats in the carb, and maybe the fuel pump.

I do agree that draining is the best solution.

If you have an antisiphon valve on your fuel tank just before the fuel line, check it to see if the little ball is sticking. If not, disregard. Ethanol can really gum these little buggers up and cause the boat to run okay at low rpms and just die when you punch it.

CantRepeat
04-09-2012, 07:23 PM
If you have an antisiphon valve on your fuel tank just before the fuel line, check it to see if the little ball is sticking. If not, disregard. Ethanol can really gum these little buggers up and cause the boat to run okay at low rpms and just die when you punch it.

Great post!

I "always" forget about that damn thing! This could very well be the root of the high RPM low fuel troubles.

Stx221
04-09-2012, 07:27 PM
I'm surprised the boat ran ok, if at all on e85, especially being carbureted. A lot more e85 is required than e10 to maintain a proper air fuel ratio. I bet the motor leans out when the throttle gets opened up as you can't provide enough fuel for it.

How long have you been running e85 in that boat?

SkiDog
04-09-2012, 07:39 PM
I'm surprised the boat ran ok, if at all on e85, especially being carbureted. A lot more e85 is required than e10 to maintain a proper air fuel ratio. I bet the motor leans out when the throttle gets opened up as you can't provide enough fuel for it.

How long have you been running e85 in that boat?

I've only had the boat since last July, and haven't put that much fuel in it. Probably 5 tanks at the most. And I don't know that its E85. I'll look tomorrow when I go by that station. There are a few here that don't have ANY ethanol.


OK, got it out. Anybody know if there is a specific part # I should buy?

SkiDog
04-09-2012, 07:40 PM
and clean up that rust would yah :rolleyes:

it's despicable

Its on my 'to do' list!

JimN
04-09-2012, 08:25 PM
I've only had the boat since last July, and haven't put that much fuel in it. Probably 5 tanks at the most. And I don't know that its E85. I'll look tomorrow when I go by that station. There are a few here that don't have ANY ethanol.


OK, got it out. Anybody know if there is a specific part # I should buy?

OK, so what did you mean by "flex fuel"?

CantRepeat
04-09-2012, 08:29 PM
OK, so what did you mean by "flex fuel"?

Hopefully some 10 or 15% fuel.

SkiDog
04-09-2012, 08:34 PM
OK, so what did you mean by "flex fuel"?

I meant to say fuel with ethanol in it. Sorry for the confusion. Id that small fuel filter one that I can get at NAPA?

east tx skier
04-09-2012, 08:35 PM
I've only had the boat since last July, and haven't put that much fuel in it. Probably 5 tanks at the most. And I don't know that its E85. I'll look tomorrow when I go by that station. There are a few here that don't have ANY ethanol.


OK, got it out. Anybody know if there is a specific part # I should buy?

What got us going was your saying Flex Fuel.

SkiDog
04-09-2012, 08:42 PM
What got us going was your saying Flex Fuel.

Yea, I know. F.U. on my part.:D

CantRepeat
04-09-2012, 09:01 PM
What got us going was your saying Flex Fuel.

Well, he did have me going a high RPM!! I guess that is better left to DS. lol

Cloaked
04-09-2012, 09:06 PM
Bad power valve in the 4160?

east tx skier
04-10-2012, 08:42 AM
Yea, I know. F.U. on my part.:D

Ha! Nice decal, Corn Star 190! ;)

thatsmrmastercraft
04-10-2012, 09:20 AM
Bad power valve in the 4160?

If the power valve were blown, it would go to full rich.

TOO-TALL
04-11-2012, 09:52 PM
Skidog,

Get her running right?

SkiDog
04-12-2012, 08:03 AM
Skidog,

Get her running right?

I have changed out both gas filters but have not run her yet. Hoping to this weekend. Maybe I won't have to change out the entire fuel line.:D

CantRepeat
04-12-2012, 08:27 AM
I have changed out both gas filters but have not run her yet. Hoping to this weekend. Maybe I won't have to change out the entire fuel line.:D

If you still have issues the first place I would check would be the needle and seat valves in the float bowls on your carb.

SkiDog
04-12-2012, 08:32 AM
If you still have issues the first place I would check would be the needle and seat valves in the float bowls on your carb.

HA! I would do that...............................IF I knew what I was doing!:D:D:D Remember, I work with wood, NOT motors.:uglyhamme

CantRepeat
04-12-2012, 09:15 AM
HA! I would do that...............................IF I knew what I was doing!:D:D:D Remember, I work with wood, NOT motors.:uglyhamme

To bad you don't live closer, it's a pretty easy check.

thatsmrmastercraft
04-12-2012, 09:23 AM
If you still have issues the first place I would check would be the needle and seat valves in the float bowls on your carb.

Last summer on vacation, my secondaries were dumping gas at idle. Found a chunk of debris stuck in the needle and seat not allowing it to close. Took maybe 15 minutes to diagnose, repair and pull the next rider. Tools required: 5/16" nut-driver and a rag.

CantRepeat
04-12-2012, 09:37 AM
It's been a while since I rebuilt a Holley, but I'm thinking the rubber on the end of the needle might be clogging the seat and not letting fuel in or maybe a slower rate then needed to maintain high RPMs.

thatsmrmastercraft
04-12-2012, 09:53 AM
I have run into more problems of engines running too rich because the needle and seat can't close from debris in the way, but it is possible to have a build-up of debris lodged up against the needle blocking fuel flow.

The screen at the carb inlet is another place for debris to build up and cause reduced flow.

Hey SkiDog.......have you looked at a spark plug or two to verify lean or rich condition?

east tx skier
04-12-2012, 10:06 AM
Tools required: 5/16" nut-driver and a rag.

That's true for about 70% of boat repairs among other things.

gatorguy
04-12-2012, 10:39 AM
That's true for about 70% of boat repairs among other things.

I've lost count of the number of times I've gotten myself or friends out of a bind with nothing more than a swiss army knife. I always have it with me except on the airplane, dang TSA.

One time on Thanksgiving on the suwannee river my friends outboard died. The fuel pick-up was complete plugged, and had it not been for the swiss army knife we would have had a really long walk to help.

thatsmrmastercraft
04-12-2012, 11:48 AM
I've lost count of the number of times I've gotten myself or friends out of a bind with nothing more than a swiss army knife. I always have it with me except on the airplane, dang TSA.

One time on Thanksgiving on the suwannee river my friends outboard died. The fuel pick-up was complete plugged, and had it not been for the swiss army knife we would have had a really long walk to help.

Fantastic. :toast:

A friend was cross-county skiing way out in the boonies with some friends when one of his binding fell apart. His pocket knife and the zip-tie he kept in his wallet (perhaps more effective than what others might keep in their wallet) saved the day and got him back on his skis.

GT500 MC
04-12-2012, 11:54 AM
Fantastic. :toast:

A friend was cross-county skiing way out in the boonies with some friends when one of his binding fell apart. His pocket knife and the zip-tie he kept in his wallet (perhaps more effective than what others might keep in their wallet) saved the day and got him back on his skis.

Depends on who you're cross-country skiing with....:D

thatsmrmastercraft
04-12-2012, 12:03 PM
Depends on who you're cross-country skiing with....:D

Well, there is that.:rolleyes:

SkiDog
04-12-2012, 09:22 PM
I have run into more problems of engines running too rich because the needle and seat can't close from debris in the way, but it is possible to have a build-up of debris lodged up against the needle blocking fuel flow.

The screen at the carb inlet is another place for debris to build up and cause reduced flow.

Hey SkiDog.......have you looked at a spark plug or two to verify lean or rich condition?

No, but I will tomorrow or Saturday. Hope to run it Saturday and see if the filters fixed it.

SkiDog
04-15-2012, 07:43 PM
Boat didn't run worth a crap today! Same problems, BUT, I did get some swimsuit thread material!:D:D:D To bad MOST of it has to go on DS!

pram
04-15-2012, 11:16 PM
do you have perfect pass on this boat?

D3skier
04-16-2012, 12:33 AM
I've lost count of the number of times I've gotten myself or friends out of a bind with nothing more than a swiss army knife. I always have it with me except on the airplane, dang TSA.

One time on Thanksgiving on the suwannee river my friends outboard died. The fuel pick-up was complete plugged, and had it not been for the swiss army knife we would have had a really long walk to help.

Fantastic. :toast:

A friend was cross-county skiing way out in the boonies with some friends when one of his binding fell apart. His pocket knife and the zip-tie he kept in his wallet (perhaps more effective than what others might keep in their wallet) saved the day and got him back on his skis.

This "one time" at band camp..... uh... never mind....... you can fill in the rest here....:rolleyes:

SkiDog
04-22-2012, 12:18 PM
do you have perfect pass on this boat?

No, but would like to add one.

SkiDog
04-22-2012, 12:19 PM
OK, I just replaced the fuel line. I HOPE thats the problem, but something in the back of my mind is telling me its not.:( idunno
Is the fuel pump in a 92, electric?

Cloaked
04-22-2012, 02:03 PM
OK, I just replaced the fuel line. I HOPE thats the problem, but something in the back of my mind is telling me its not.:( idunno
Is the fuel pump in a 92, electric?
No. Mechanical. Mounted on the block just above the oil filter. Easy replacement.

mayo93prostar
04-22-2012, 02:38 PM
Dog,
I recommend to check the screen in the pickup tube in the tank and the anti-siphon valve on top of the tank. I think next option may be to replace fuel pump. Or it is carb problems as others have noted. Good luck.

JimN
04-22-2012, 02:41 PM
Dog,
I recommend to check the screen in the pickup tube in the tank and the anti-siphon valve on top of the tank. I think next option may be to replace fuel pump. Or it is carb problems as others have noted. Good luck.

Or, check the fuel pressure, check the spark intensity, see if the carb is leaking into the venturis, add gas to see if it runs better or worse, check the float to see if it leaked, try a different fuel source,......

SkiDog
05-05-2012, 09:39 AM
Took my boat out today. Ran great on the hose for about 30 minutes, so I decided to take it to
real water. First thing, was it was hard to start. Started right up on the hose, but once in the water, it took it a while to finally start. Back it off the trailer and idled out. Running fine, all gauges are looking good. Volt meter MAYBE a little suspect. It was running at about 12.5 volts. Running dual batteries and running on both batteries too. Get it up to about 2400 RPM's and after a few seconds it just completely dies. Back off the throttle and it stays running. Throttle up again, same thing. Runs great at 1900 and below, but not above. Anybody got ANY ideas? NOTE: I did not put any fuel additive in the tank at the end of last year, and I topped it off today, but it only held about 7 gallons.

FIXED!!!!!!!! New fuel line from the tank to the pump, did the trick. Running like a scalded dog now!:D:D:D

Footin
05-05-2012, 11:16 AM
Ethanol probably ate it up.

mtajpa
05-05-2012, 12:27 PM
Great to here you got to the root of the problem. Dissection of the fuel line would be interesting to see. Probably will look like the internally collapsing exhaust hoses.

Lumbergh
05-05-2012, 12:34 PM
I noticed a while back that the 3/8" fuel hose is the #2 item on skidim's top seller list, and after seeing the exterior of mine in the bilge, I can see why.

Easy project and cheap too. Glad I did it just because it seemed like a good idea.

Glad it solved your problem!

TOO-TALL
05-05-2012, 09:32 PM
FIXED!!!!!!!! New fuel line from the tank to the pump, did the trick. Running like a scalded dog now!:D:D:D

Glad to hear your all fixed up.