Engine dies in the chop - like no fuel

[lcichon]

Hi, I have a 1987 Wellcraft Classic 18. OMC Cobra 4.3L engine. New engine put in last summer. Was out for the weekend and the boat was running fine. After a particulary choppy run to the marina, it started acting like the fuel was cuttoff whenever the lake gets choppy. Plenty of gas, engine looks fine, and it runs great in smooth water but as soon as it starts getting rough it runs crappy and then the motor just dies as if I ran out of gas. I suspect loose wiring but can't find anything. Any suggestions on what to check?

Thanks for your time-

Lee

 

[lcichon]

Re: Engine dies in the chop - like no fuel

A friend did it and I can't ask him to do that. It's run many times since the new engine was put in without this happening so I think it's a new development. Thanks

 

[lcichon]

Re: Engine dies in the chop - like no fuel

This one is going to be a bit of a pain to trouble shoot as it only happens intermittently.

Let me ask a few questions.

1. When it stalls, does it start right back up? Does it start easily?

It starts, but sometimes I have to crank it 2 or 3 times before it starts again.

2. If not, does simply waiting for a bit allow it to restart?

Haven't tried it

3. Have you paid attention to your guages when it happens? Anything out of the norm for your boat?

Gauges are normal, however my oil pressure gauge doesn't work

4. When you say crappy before dying, do you mean it misses, lacks power, backfires, etc.? Anything specific?

Misses and lacks power, no backfires. Like it's 'running out of gas'

5. Any abnormal noises or sounds from the engine area?

No.

Thanks!

 

[lcichon]

Re: Engine dies in the chop - like no fuel

Mechanical

 

[lcichon]

Re: Engine dies in the chop - like no fuel

Thanks, I will give it a shot! A friend of mine suggests bad gas and thinks that when the boat angles water is mxing with the gas in the carb and told me to throw in a bottle of Heet to see if that clears it up. What do you think of that theory? He also suggets bringing a can of carb cleaner and spraying it into the carb after the boat dies to isolate the problem with either the ignition or fuel system.

 

[sailsmanship]

Re: Engine dies in the chop - like no fuel

mine did the same thing.. It was a clogged filter sock in the tank. Would run great untill choppy. the gunk in the tank would collect on the sock when stirred up. then drop off when it was calm..

 

[lcichon]

Re: Engine dies in the chop - like no fuel

Is there a way to flush the gas tank?

Thanks for the great advice guys! I'll head out on the boat with a few supplies and see what happens and let you know.

Lee

 

[lcichon]

Re: Engine dies in the chop - like no fuel

Holy crap, I finally found the problem. It was a bad starter solenoid. The power lead coming from the ignition coil went to the R terminal on the solenoid, then it went to this cylinder part with "external resistor" written on it, and that's where the power lead from the fuel pump picked up juice. It then proceeded from there to go to the alternator. So when I traced the wire all of the way back to the solenoid and wiggled the R terminal the fuel pump would turn off and on. I could even get the fuel pump to go off and on by stomping on the boat deck by the engine or tapping the solenoid with a wrench. So I replaced the starter and solenoid last night and it starts right up every time. However, I still suspect faulty wiring might have been the the cause for the solenoid failure because the wire I'm talking about seems to be wired to power on one side and ground on the other and heats up with the key turned on but without the engine running. And the R terminal on the solenoid appears to be the ground but if I disconnect it the engine won't start. Any help understanding how this stuff works and should be wired would be greatly appreciated. Thanks!

 

[lcichon]

Re: Engine dies in the chop - like no fuel

And by the way I have an electric fuel pump, not mechanical. Sorry-

 

[Haut Medoc]

Re: Engine dies in the chop - like no fuel

And by the way I have an electric fuel pump, not mechanical. Sorry-

Hmmmm, that would matter.....:redface:

 

[chiefalen]

Re: Engine dies in the chop - like no fuel

You found the problem good. When you get a chance clean all the grounds also.

You will be surprised how many problems get solved with clean grounds. Take em off clean em good with sandpaper and the place they ground to also. Spray them with corrosion pro.

Good luck!

 

[lcichon]

Re: Engine dies in the chop - like no fuel

Thanks guys. Is that R terminal on the solenoid supposed to ground out when the key is on? That wire is still getting hot to the touch when the key is on although now the fuel pump runs as it should and the boat starts very easy. I just want to make sure the wiring is correct and I don't burn up anything (else?). Also, does anyone have a wiring diagram of a 1987 4.3L OMC? Thanks-