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mike781matco
04-05-2012, 01:30 PM
i have a 1979 stars and stripes with the pcm 351. heres the problem. every time i take it out it runs graet for about 30 mins and dies. the temp never exedes 220. when i bought the boat the previous owners converted it to electonic ignition. ive repaced.... plugs, plug wires, ignition module, coil, thermostat, impeller, resistor, batery, oil, checked timing, and raised the coil off ot the engine a few inches. i thought it was a cooling probem so i removed the thermostat and ran at 175 deg. and still died. after it dies i lift the cowling and the coil is very hot to the touch (the third coil ive tried) and once the boat is cooled down enough it fires back up (after about 20 mins) does any one have any insight for me?

thatsmrmastercraft
04-05-2012, 01:36 PM
A few things come to mind. The correct thermostat should be a 160 degree (some of the earlier were 143). This should help some for heat soak. Is the one inch carburetor spacer still in place under the carb? If not, that can be a culprit. An epoxy filled coil is way more heat resistant than an oil filled coil, though I still have an oil filled coil and have no start up problems. Where is your timing set? It should be at 8 or 10 degrees as I recall. If it too far advanced, your engine will operate on the hot side.

mike781matco
04-05-2012, 01:48 PM
it a 180 thermostat the carb has the 1 in spacer plus i added an aditional 1 in throtle body spacer timing is set at 6 deg btdc thats what was said in the owners manuel

thatsmrmastercraft
04-05-2012, 01:52 PM
I would check what temp thermostat the manual says, but pretty sure it's 160. Fresh spark plugs, dist cap and rotor go a long way towards starting when hot. I would make a point of opening the engine cover next time you shut the engine down for a bit and see if that helps the restart.

mike781matco
04-05-2012, 02:06 PM
ive run it with no t stat and every time it dies i open the engine cover i was thinking because its trhe origon al alternator that its producing less voltage when it gets warmed up

thatsmrmastercraft
04-05-2012, 02:17 PM
How long have you had the boat, and is this a new problem? The too hot coil definitely sounds like a problem. Was the ballast resistor bypassed when the electronic ignition was installed?

TRBenj
04-05-2012, 02:18 PM
If you are really running at 220 with a thermostat and 175 without one, then you have a severe cooling issue.

You should be running a 143 'stat in that carb'd PCM, which should keep you right around 160 degrees. Anything over 200 is overheating.

The coil *might* be heating up and causing your problems... but thats a stab in the dark. Fix your cooling problems first.

ccowell
04-05-2012, 02:50 PM
I have a 79" as well and I put the electronic points in it and it messed everything up. The boat ran hot, over heated, new flat spot and rebuilt the carb everything went wrong. Finally I called pertronix and they said that they would take it back for a full refund, and I could not have gotten it out of my boat quick enough and go back to my mechanical points and dwell meter.

One thing that I do know is that you have to run the correct voltage coil. The electronic ign needs a specific coil voltage to go with the points. That could be your problem. The coil heats up and cuts out on you. Try going back to the points and see what happens.

ahhudgins
04-05-2012, 03:38 PM
How long have you had the boat, and is this a new problem? The too hot coil definitely sounds like a problem. Was the ballast resistor bypassed when the electronic ignition was installed?

^^^^^What he said.
Did this problem start as soon as you bought the boat? If not, how long before it started to shut down on you? Did you replace all of those parts before or after the problem started?
Does it die while the motor is running or does it not restart after shutting down. The more information you can provide, the better.

I've replaced two point systems with the electronic ignition (mine and a friends) and had no issues, but everything was original in both boats (coils). Took the points out, bypassed the resistor and they worked great. Not all kits bypass the resistor.

Your temperature concerns me (220) and I would start with that issue first. Buy (or borrow) an infrared temp gun (less than $50) and check your actual temp at the thermostat housing to make sure your gauge is correct. I wouldn't keep throwing parts at it until I got my temp down in the 140-160 range.

mike781matco
04-05-2012, 03:56 PM
ok ill start with a thermostat and the problem happened when i first got the boat ive also ordered a new water pump the boat runs fantastic for the first 20-30 mins like brand new hitting 50 mph then slowly dies from there

mike781matco
04-05-2012, 03:57 PM
ive also put in a new balast resistor

mike781matco
04-05-2012, 03:59 PM
ive replaced the balast resistor

mike781matco
04-05-2012, 04:06 PM
ran it with no thermostat temp did not exeed 120 and still died. does this boat have an ignition module? if it does where is it?

ctjahn
04-05-2012, 05:36 PM
Does it stumble at all?

I had one where the petron went bad {causing wierd issues but mostly a stumble between 5k and 7k rpm) but would only show up when HOT on the racecar. I did much of the same of what you did until I replaced the petron. Now I carry a spare for the racecar. (From research I found out one of the magnets was going bad in the ring {Not the unit} from when I forgot to turn the master off - ign was on even though the car wasnt)

Still running points in the boat... (but it is on my list with wires, cap, rotor, coil, etc - or should I say is still on my list to do this season)

Good luck! Please post what it is when you find out!

Cj

ahhudgins
04-05-2012, 06:52 PM
ok ill start with a thermostat and the problem happened when i first got the boat ive also ordered a new water pump the boat runs fantastic for the first 20-30 mins like brand new hitting 50 mph then slowly dies from there

Before you install a new water pump, check the fresh water inlet on the bottom of the hull by removing the hose from the inside of the boat. Make sure the inlet is clear and then check the strainer on the transmission cooler. Small sticks and weeds can get inside the strainer and get trapped around the outside edge so it's a good idea to back flush the strainer with a garden hose.

Have you tried sticking the water pick-up hose in a 5 gallon bucket of water to make sure it's picking up enough water?
120 still seems a little high for an engine with no thermosat and picking up cool lake water.

mike781matco
04-05-2012, 09:11 PM
ive got the mallory e spark conversion kit and reeplaced the module with the newer unilite ... no difference. i have it hooked up to the inboard version of earmuffs looks like a plunger, whule its in the drive way and the impeller is pumping strong. so im still poking in the dark im about to install a new alternator and pump tonight ill see if that makes the slightest bit of difference.

ahhudgins
04-07-2012, 09:32 AM
ive got the mallory e spark conversion kit and reeplaced the module with the newer unilite ... no difference. i have it hooked up to the inboard version of earmuffs looks like a plunger, whule its in the drive way and the impeller is pumping strong. so im still poking in the dark im about to install a new alternator and pump tonight ill see if that makes the slightest bit of difference.

I suggested the bucket method because when you are using the plunger or the hose connected to the transmission cooler (the method I use) the water is being pushed into the impeller housing. You want to make sure the impeller is actaully able to suck the water out of the bucket at idle. Shouldn't take more than 10 seconds to empty a 5 gallon bucket. You could also have a faulty temp sending unit or gauge and the engine isn't really running at 220that's why I would check the actual engine temp with a infrared gun. You can pick up one pretty cheap at Norther Tool.

Table Rocker
04-07-2012, 11:25 AM
One thing I would suggest is keeping a can of starting fluid in your boat. When the boat dies, give it a shot of starting fluid before trying to restart. If it fires, you are dealing with a fuel issue. Vapor lock would be your most likely fuel issue. If it doesn't fire with the starting fluid, you are dealing with an ignition issue.

A can of starting fluid is a cheap tool to tell you which path you need to go down.

I would add: Ethanol blend gasoline causes more vapor lock problems than the 100% gasoline that your boat was built to run on.

All that being said, your boat is running too hot and that is a primary concern.

1redTA
04-07-2012, 11:50 AM
I think you have a heat related issue such as vapor lock or an electric item affected from the heat. I've had ignition coils work great cold but when they warm up a crack effects the ignition system.
my 81 uses the 143* thermostat; running the raw water pump on a bucket will let you know how it performs how is the impeller? any leaks in the water lines ( air or water )
and to much ignition will also cause over heating

sorry for the rambling

liledgy
04-08-2012, 10:42 AM
My buddies 78 had similar issues that drove him nuts for a while. A year later he figured it out, the fuel pickup in the tank was full of crud. He cleaned it up had the boat has been running fine since.

cbryan70
04-08-2012, 12:21 PM
When it does not start when its hot try closing the choke flap on the carb. Sounds backwards, but when mine heat soaks that is what I do and it works....

markismm
04-10-2012, 02:21 PM
I had the same exact issue (except I had no temperature problems) and I found out that it was a fuel delivery problem (clogged inlet tube inside the gas tank - actually very common with older boats). I think you need to try to narrow down whether or not you are dealing with a fuel delivery problem, a spark issue, or some sort of overheating issue. The starting fluid method suggested above will tell you if it is fuel delivery or spark related. Once that is narrowed down, you should be able to diagnose the problem very quickly. If you narrow it to fuel delivery, look at the fuel pump, fuel tank, water fuel separator and finally the carb. If it is spark related, look at the coil and see what the ohm rating on it is. You need to check the specifications of the ignition module you are running, but typically I believe you should be running a 1.5 ohm coil with a ballast resistor or a 3 ohm coil without. If you end up wanting to try another distributor and ignition module, I can loan you my old one which is in perfect working order along with the coil that goes with it. Shoot me pm if you are interested. If you pay shipping, you are certainly welcome to try it out. Thanks. Mark.

markismm
04-10-2012, 02:25 PM
Just noticed you are in the "south". what part of the "south" are you in? what lake do you boat on typically?

sam196370
04-11-2012, 01:51 PM
I had a fuel issue too, worthwhile to remove tank and have cleaned.

Last summer I had that problem and turned out to be a hole in exhaust which was causing engine to lack O2 then stall and not start for 30+/- mins. Try running it with cover open and if it still dies after 30 mins then it's probably a fuel issue.

mike781matco
04-14-2012, 12:10 PM
I'll check into the fuel tank. Will not fire on starting fluid but has spark when I hit the throttle I can see fuel squirting in the carb. New t stat new impeller timing is set at ten but don't know if that's correct thinking of just going back to points I discovered a crack in the head dripping water but was told its not a problem I also run ethanol free leaded fuel

mike781matco
04-14-2012, 12:10 PM
Florida south lol lake dias