1990 OMC 4.3 quits after moderate use.

[robv75]

I have a four winns with the above engine, it quits at times and will not restart. But after sitting over night will start again and seems fine. We run it for a while and then it just cuts out and won't restart. It has an inline electronic fuel pump and a water/gas filter below. I have an extra quart of oil in the crankcase, could that be fouling the plugs, then draining overnight?

 

[Don S]

Re: 1990 OMC 4.3 quits after moderate use.

DO NOT exceed the full mark on the dip stick. It won't cause plug fouling you mentioned, but it will aireate the oil from the crankshaft hitting it and cause lifters to rattle (and collapse) and can damage the bearings because of the air. But I doubt that is your problem.
Have you checked to see if you have spark when the engine fails to start, or is fuel lacking at the carb?
That is the first thing you need to find out. No sence chasing a fuel problem if you don't have spark.

 

[robv75]

Re: 1990 OMC 4.3 quits after moderate use.

DO NOT exceed the full mark on the dip stick. It won't cause plug fouling you mentioned, but it will aireate the oil from the crankshaft hitting it and cause lifters to rattle (and collapse) and can damage the bearings because of the air. But I doubt that is your problem.
Have you checked to see if you have spark when the engine fails to start, or is fuel lacking at the carb?
That is the first thing you need to find out. No sence chasing a fuel problem if you don't have spark.

 

[robv75]

Re: 1990 OMC 4.3 quits after moderate use.

Thanks Don, I tried to get to the dist. cap but can't seem to get the air cleaner off due to the engine cover being in the way. I have not taken out a spark plug yet, but It doesn't make sense to me that I would lose spark at night and then have it again in the morning without doing any thing to the engine. That is why I have been looking at the fuel system. I figured that if I have a clogged something or other it may dislodge itself overnight and allow the engine to run again. I will get the extra oil out of there though, thanks.

 

[Don S]

Re: 1990 OMC 4.3 quits after moderate use.

It doesn't make sense to me that I would lose spark at night and then have it again in the morning without doing any thing to the engine.

Trust me, it happens all the time. It's not a night and day thing, it's all about heat. Coils can go bad with heat and work fine when cold, ignition parts are the same, connections with a little corrosion buildup more resistance with heat.
Also sounds like your boat may be lacking in some maintenance if you can't even get to the distributor cap. When was it last tuned up?
I'm not saying it's not a fuel problem, just saying it's a possibility. When it stops, your first job in tracking down the problem is to find out if you are loosing spark or fuel.
Without that information you are going to be tinkering and hoping you find a cause of some kind.

 

[Don S]

Re: 1990 OMC 4.3 quits after moderate use.

IF you do find that it's dieing because of a fuel problem, here is a way to test the boats fuel system to make sure you are getting fuel to the pump.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=24;gtid=1107009

 

[robv75]

Re: 1990 OMC 4.3 quits after moderate use.

thanks again, a little understanding goes a long way. I bought the boat this summer. It had a rebuilt engine and new manifolds on it. As far as a tune up goes, I don't know. I can't seem to get the plastic cover that is over the carb over the bolt that attaches it because it hits the engine cover when I try to lift it off, I guess I'll have to cut a slot in it to clear the mounting bolt. I don't want to start taking the rear of the boat apart, but I am going to have a hard time reaching the distributor cap even when I do get that plastic cover off. Is it necessary to unscrew the rear engine cover and seats to get to the engine enough to work on that stuff?