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Boat is powered with 350 Crusaders. The stbd engine is cutting out for no apparent reason. Water temp, oil pressure, fuel flow (Floscan) is normal. At idle, the engine will just stop. Wait a minute or two and it will start up and run normal for a while, then cut out again. At higher RPM, it will lope a little and then cut out. After a few minutes it always restarts easily. Distributor is electronic (no points). Anyone have any ideas on the cause?

Boat is in Palm Beach Gardens, FL. Can someone recommend a mechanic in that area? Thanks.

Leo,

You've almost certainly got a fuel delivery problem on that side. Possibilities include blocked line, fuel pump going bad, air leak, or clogged vent. Check all of your fittings for air leaks. Bruce may have some more suggestions... Ignition timing?

Along time ago I had a problem like that with a SB Chevy/IO no one could find the problem.
Turned out to be a ballast resistor.
This may or may not help but its a thought.

A sudden stop is normally ignition related. A gradual slow down to stop is normally fuel related

Check your coil. If there is a problem in the windings it will break down under load.

Might be a heat related problem with the ignition (hei?). Try running with engine cover off and a fan blowing across the ignition module. If the engine runs better you probably have degraded insulation in the module and/or a bad ground.

If you can pinpoint the problem areas, you can swap parts with the good engine to verify before spending $.

When the coil cools down the engine will start as normal. It will die again when it heats up. From cold, is there a standard time that it cuts out? Mine quit after about 45 minutes running at idle. After replacing the coil, no more problems. Took me quite a while to figure this out, but after buying two coils at $40 each, my problem was solved.

Thanks for the clues. Joseph, after a cold engine start, it will run for about 5-8 minutes and cut out. It will restart almost immediately, but cut out again after a few minutes. When I get back to the boat again i'll take the coil off the other engine and give that a try. Hopefully that's it.....

Coil or module sound like the place I'd start to look.

If carb, maybe a bit of water or dirt in a bowl or jet.


As said by others, I'd start by swapping Coil to running engine see if problem follows.
If not...unswap and try swapping Module



A quick way to try to clean out carb a bit...Get RPM up a bit and cover intake quickly with your hands till motor almost stalls, then release. Sometimes the vacuum created will suck that pain in the Arse droplet of water thru or that lil' piece of dirt.

Try switching the two coils. If the problem switches sides that is it. One of the advantages of twin engines.

Carl: I call that the Redneck carb rebuild! Always worth a try!

Rawleigh wrote:Try switching the two coils. If the problem switches sides that is it. One of the advantages of twin engines.

Carl: I call that the Redneck carb rebuild! Always worth a try!

Rawleigh---If that Redneck Rebuild doesn't work the next step up is taking carb off, flipping it upside down over a bucket, and giving a good shake, then reinstall. Can't say that hasn't got me out for an Emergency Fishing Trip when rebuild kits were on backorder.

My bet is its electrical. 13 years ago, I changed the points ignition to brank new Merc Thunderbolt iginitions on my B28. Both engines ran great for a half hour, then the stbd one would sputter and fart and not hold rpms before dieing. After a half hour, it would start back up and run fine for another half hour. Mechanics swapped everything trying to figure out the prob but nothing worked. Finally, they swithched the pickup on the distributor. Voila! Prob solved. All parts were less than 8 weeks old. The pickup was around $75, but I was stuck out on Nantucket and it cost me about $800 in labor.

Leo,
Would it possible to record a video for listening purposes? This kind of thing could more be diagnosed with some trained ears exactly how engine starts to die from beginning to not running. What has been suggested so far are good ideas to cart with but an ear on that engine would more accurately narrow down.

Rocky, your kidding about the video.....right? The engine shuts down like you're turning off a light switch.

Leo no, not kidding. When you stated higher rpms would lope then die could be fuel related, so at idle suddenly dying might not be ignition related but I thought all the collective "ears" here might be able to shed some light on direction to search.

Rocky brings up a good point.
Ever hear an engine run out of fuel at idle? It can runs lean for a sec bringing up RPM right before it quits.

A bad module can be abrupt like shutting ignition....also had a tach wire come loose and cause motor to just shut down...

Coil, resistor...I have little clue.


May help narrow your search...can't hurt.

Guys, thanks again for the clues. I'll be back at the boat this weekend. If I get the problem solved, I will post the solution.

I may be the least qualified mechanically on this board, but I had a problem almost exactly the same and it turned out to be a fuel pump issue.

Pete - I will put my lack of mechanical abilities up against your any day.

Ian.

Did you try taking the fuel filter off and dumping it into a bucket or container and looking for water. I had a similar problem some years ago when I went to get Elusive in Dania, Fla. I had to dump the filters about 6 times on the way to Stuart. Water will bog or shut down the motor and when throttle returned to idle the engine will continue to run. On the crusader you also have the little can filter mounted off the manifold. I kept dumping the in line fuel water filter. It would not suprise me to find a bunch of junk and water in the filters. Good luck

The coil and resistor have been replaced. The problem has changed somewhat. From a cold start, the engine starts, runs briefly and shuts down. I can restart and it will run for a long time. On a warm start it doesn't do that brief shutdown. We ran it at idle and cruise speed for about 20 minutes with no problem. We thought the problem was solved with the coil replacement. Next day we headed for the inlet, and after idling for about 1/2 hour the engine loped briefly and shut down. After a few minutes, restarted and headed back to the slip with no additional shutdown. I guess now the next step is to replace the fuel pump. I read on another blog that if the pump diaphram is bad it will push fuel up the tube that runs from the pump to the carburetor. I'll check that out next time at the boat.

ljmauricio wrote:it will push fuel up the tube that runs from the pump to the carburetor. I'll check that out next time at the boat.

That's what that pump is supposed to do... Feed fuel to the carburetor...

On marine gas mechanical fuel pumps the normally open vent hole
has a barb and a hose that runs up to the side of the carb to prevent that fuel from going into the bilge and going boom if the diaphragm gets a hole or ruptures.

With a ruptured diaphragm that vent line is pumping extra fuel into the carb directly into the throat where it would be easy to flood the engine at lower rpm's.

ljmauricio,
Have you checked the quality of the fuel possible water contamination or I hate to say it ethanol issue maybe?. Also check for bad ground connections at battery and at engine. Could it be a bad ignition switch or related wiring?
Pete Fallon

It turns out the first response by Capt Patrick to my issue was correct. Air leak at the AC filter gasket was the problem. Didn't know there was another filter back there until we changed the coil resistor. Thanks to all who responded. Also to Bruce and Pete who recommended The Ways and Chris Hodge who hooked me up with a mechanic named Dan Coppola who says he knows you guys. Dan seems to know his stuff.