Hi All, I have '93 OMC 7.4L HO with King Cobra (Cone Clutch). Model # 744CPEJVB. It has the Spitfire/EEM ignition system. Earlier this season my boat started to cut out just for a fraction of a second at around 2800 RPM. As if it's losing all spark. When I back off the throttle a little it stops and the more I try to get on the throttle, the more frequent it cuts out. I noticed whenever it happens the voltage meter pegs high and it trips one of the breakers on the exhaust riser. I had the alternator checked and it is fine. I recently changed all the shift cables thinking it might be the shift interrupter, they were all original afterall - not it. I'm thinking it has to do with the ignition system. I tested the coil, it's within spec. I'm wondering if it could be a bad sensor or the module. Which would be more likely to fail, all being original? Is there something else I should try/test? Thanks in advance
Howdy,
Welcome aboard!
Well, I am sorry to say that you have an ignition system that is no longer supported by anyone. The module for that engine is not available from anyone anywhere, I don't think you can buy the crankshaft sensor either (I did find the knock sensor though) .
Now having said that, if you have circuit protection activating(CB popping) , you have a short (to ground) someplace, and/or a poor connection in a ground or crimped wire connection that is coming loose or is severely corroded.
If it were mine, and I wanted to continue running that engine and drive, I would remove the entire ignition system and replace it with an Volvo Penta, MSD, Mercruiser Thunderbolt V or other aftermarket marine ignition system. (although I am not sure how well the shift interrupt switch would interface)
You probably know that OMC went out of business in the late 90's. That particular engine and drive were only produced for a few years and (the drive) is NOT "the same" as a Volvo. Evidently, OMC went all alone with the Spitfire ignition system as the ECM's weren't common to any of the Volvos that followed and very few OMC parts are left.
Sorry about that,
Regards,
Rick