'92 OMC 5.0L Ford Misfire

[keirstrw]

Hi,<br />I have a '92 OMC Cobra 5.0L for that misfires. The engine will misfire occasionally when I am on plane and the engine is running at ~3800-4000rpm. When I adjust the trim, it misfires the entire time I am adjusting the trim. It will also run a little rough after about 20 minutes or so when I am just idling around. After the rough idling, it is usually hard to restart after shutting it off. I had new plugs and coil installed this year, and the carburetor is clean and the gas is new. <br />Any insights would be greatly appreciated!<br /><br />Thanks!<br />Bob

 

[Haut Medoc]

Re: '92 OMC 5.0L Ford Misfire

What about points, wires, timing? Especially wires. Is this a new problem?

 

[keirstrw]

Re: '92 OMC 5.0L Ford Misfire

It is not a new problem, it started missing a little at the end of last season but is worse this year. The timing is OK because when I had the new plugs put in, they adjusted the timing. It doesn't have points, so I think I may try some new plug wires. Any other thoughts?

 

[jka]

Re: '92 OMC 5.0L Ford Misfire

Bob,<br />I had/have the same prob with my OMC 5.0 re misfires or stalls momentarily when the trim switch is applied. Otherwise the engine runs perfectly. Mech said the alternator was bad. It was replaced but the misfire continues. They've been unable to pinpoint the issue.<br />One mechanic said the brushes on the trim motor may be bad. I wish I had an answer as well.