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43 stalling hot hard start

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matt123

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"I have a 2001 4.3 with 2 bbl

"I have a 2001 4.3 with 2 bbl carb. The boat runs fine for an hour or so. About 3000 rpm under load (pulling skiier) the engine will sputter and stall. After which boat is very hard to start, until cooled. Boat will restart then die out again at any rpm range.
I've checked both inline fuel filter and fuel/ water sep. filters both are fine. Electric fuel pump has good steady flow. Carb. cleaned, float seems fine and excel pump is on highest setting. Added Sea-foam to gas etc. Still the same problem. Seems like the problem has gotten progressively worse over the last 2-3 times I've had it out.
The only thing that seems odd is the coil was very warm to the touch today, hours after the engine had cooled (out of the water at home), possibly a bad coil?
I'm still kinda leaning towards a carb problem, but it was so clean inside I don't see it being bad. What do you guys think?
Any help is greatly appreciated."
 
"Matt:

Did you check for sp

"Matt:

Did you check for spark when it dies? I would consider changing the coil to start. The excessive heat is a telltale failure sign. If it was a carb problem, it wouldn''t just happen at 3K RPM after an hour of use.

If you want to prove that the coil is the problem, take the new coil with you next time out and an ohmmeter. Before leaving the driveway, measure the ohms from the coil tower to ground and write it down. Remove the + coil wire and measure its ohms to ground and write it down. You now have a baseline to work with.

Now when the engine dies, take an ohm reading of the coil tower AFTER YOU SHORT THE TOWER TO GROUND TO REMOVE ANY RESIDULE HIGH VOLTAGE. If the ohm reading is infinity, the secondary is shot due to excessive heat buildup. Change the coil and if it fires right away you have positively ID'd the problem."
 
"Thanks Guy for the quick repo

"Thanks Guy for the quick reponse,
No we didn't check for spark on the water, just tried to get her back to the dock. It would restart after a couple minutes, but then sputter and die a minute later. When we did check the coil wire out of the water, there was a green paste/putty on the coil tower and wire. Is that something that could also point to a coil problem? Or is that a anti-spark marine type of insulation. The coil is original, plugs wires cap and rotor have been changed resently.
Also wondering if the fuel pressure safety switch could also be a problem, is there a way to test it's operation? Just trying to narrow down all possible solutions.
I ordered a new coil and plugs, hoping thats the problem.
Thanks for all the help."
 
Matt:

The green paste/putty

Matt:

The green paste/putty was on the inside of the coil top? It may be an anti-corrosion high voltage silicon grease. Would have to see it.

Many people don't realize that greasy dirt in a moist environment can conduct electricity under the right circumstances especially on top of a battery or around high voltage ignition components. This condition can drive a person crazy trying to figure out where the "Gremlins" are causing an intermittent problem.

Disconnect the engine main harness "barrel plug" and look inside of both ends for corrosion. Make sure your battery is in tip top condition with clean terminals.

Let us know if the coil and plugs cure the ailing beast.
 
"matt;
By your reference to &

"matt;
By your reference to "fuel pressure safety switch" I am thinking you mean the oil pressure switch that cuts power to the fuel pump on low oil pressure, right?
If that is bad, your carb would be dry of fuel, and you would get no fuel shot when the throttle is pushed forward as you look down the throats (engine off). This would be one way to check that possibility out.
The green pasty stuff is a corrosion product of copper and water. It sounds like you are getting moisture in there. You should seal all ignition wire connections with silicone grease so moisture cant get in. If you did not use high quality marine wires the first time around, I would change them out. It does not pay to put cheap Walmart junk on a marine engine, in the long run.
Ignition is the weakest link in any engine; it should always be suspect first.
Rod"
 
"The green putty is inside the

"The green putty is inside the coil tower and the ignition wire to the coil, but not on the cap or any other wires. Kinda like body filler before it hardens, it's really packed in there too. Almost to the point that it seems like it would inhibit a good spark. My bilge is always dry, other than normal minor condensation. Could it get to that heavy of a greasy consistancy from corrosion?
It's not a flaky green/white mix like you get on a old battery terminal, it's like a super heavy weight green/brown grease. Beats me, I've never seen anything like it.
Battery is only a season old with a fresh charge and terminals were cleaned and checked pre-season. Plug wires look brand spankin new too.
Sorry, yeah I was talking about that oil pressure switch, that was my fault. I read somewhere that it could cause problems like this if it went bad. My carb had fuel in the bowl when I disassembled it to check the float. And I still get a solid stream of fuel in both barrels when I goose the throttle. So from what you said I'm guessing I can rule that out.
Is there anything else that you guys can think of that I should check.
Still leaning towards the coil, hopefully that cures it.
Thanks Guy and Rod."
 
"That green stuff just doesn&#

"That green stuff just doesn't sound right at all. I would either clean it all out of there, or replace the affected parts. It may very well be high resistance and the main cause of your problem.
You may have developed a machine that creates matter!! Maybe get a patent application going. I wonder what the heck it is though?
Rod"
 
"Beats me Rod, from what I und

"Beats me Rod, from what I understand marine coils are oil filled. Is it possible that the coil internals could have gotten so hot that it melted and pushed this stuff out? Although there doesn't seem to be any cracks or holes in the coil.
Only thing I'm wondering is if it is some sort of marine voltage grease, do I need to find more when I replace the coil?"
 
"Matt:

You don't need a

"Matt:

You don't need any grease on the inside of the coil output. If you feel you must put something on there, use a thin layer of dielectric grease applied with a Q-tip on the conductor portion. If you put it on the rubber boot, the boot will slip off and the wire with it on you while under way."
 
"Hey guys,
I'm back with

"Hey guys,
I'm back with some bad news. Just got back from a weekend away with the boat and new coil.
Installed and tested the coil before we left, no problems.
We took the boat out saturday morning, it ran great for 2 hours then same thing. Just died at 3k RPM. Fired right back up ran for maybe 5 minutes. But the third time the engine locked, no crank, seized.
We got towed back, and tried turning the crank by hand with a wrench, nothing. Big floating paperweight...bastard boat.
I don't know whats inside, haven't really felt like looking, maybe a spun bearing, blown rings, dunno.
I just have no idea why it seized, the boat is always taken care of, never neglected. No low oil pressure, no overheating. I don't get it, pisses me off...but what can you do."
 
Wonder if it ingested some wat

Wonder if it ingested some water?
You should try pulling the plugs and turning it over with a socket.
Rod
 
"Rod,

It did ingest water.

"Rod,

It did ingest water. We changed the oil two times, and everything seemed to be ok. We took it out again with out the thermostat in and she ran great for 3 to 4 hours and thought we ran out of fuel. I filled her up up with fuel today only to see she took 8 gallons, so we now know that the problem wasnt fixed and we didnt run out of fuel. I put the thermostat back in today and we got 2 hours out of her before she started to die again. She ingested water again today too. Any ideas?"
 
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