engine just quits, why???

[liesight]

I have a 1986 omc 3.0l, when at either 3/4 throttle to w.o.t, at any given time the engine will just quit, almost as if I turned the ignition off. It's very quick and once in a while it will do it when I'm at w.o.t and I pull back on the throttle (and we are talking fairly slow just to 3/4 throttle or so.<br />I have gone over this boat...it's not the fuel system (new fuel pump), it's not the ignition (new ignition), it's not the valves or any part of the drive train (just rebuilt), it's not the timing (just timed).<br />As soon as the boat dies, when I put it in neutral and turn the key, the boat starts again, could it be one of the throttle position sensors or maybe even a ignition switch somewhere I don't know about. Could it be a bad fuse somewhere?<br /><br />Any help would be great. <br />thanx

 

[Walt T]

Re: engine just quits, why???

If this has a kill switch, thats the first thing I'd check. You say its not the ignition or the fuel, but you are missing something. It sure sounds like an ignition problem to me. Replacing the fuel pump doesnt guarantee its not a fuel problem. You dont say what you replaced, just 'new ignition'. All that means is that the problem most likely does not lie in the parts you replaced. If you are paying a mechanic to throw parts at it, you need to find a mechanic that can diagnose.

 

[liesight]

Re: engine just quits, why???

I've tested the ignition side myself, making sure to check every wire and connection I could. The new fuel pump was followed by a series of check, like anti-syphon valve etc. Starving from fuel would kill the engine, but it happens to quick and harsh, I don't think it's fuel.

 

[flashback]

Re: engine just quits, why???

Walts right, you could have the best fuel pump in the country but if the filter is stopped up the engine is gonna starve. same with ignition, new points or module dosent mean the spark plugs, or wires are good.......

 

[liesight]

Re: engine just quits, why???

I may have found the problem, thanx to all for your help, I will not be able to test boat til next weekend but I think the interrupt switch was ingauging while at high speeds, I believe the override cam switch was not engauging properly, I made adjustments, I will let everyone know.