4.3 OMC bogs down

[stormin4]

I have a 1987 21-foot Sea Ray Seville with a 4.3 liter OMC. The motor has started bogging down on acceleration, mainly after about 2,800 RPMs and won't reach peak RPMs and top speed (previously 43 mph, now 33 mph). Bogging becomes particularly prounounced when I hit the trim switch to trim it. I have added fuel treatment, octane booster and cleaned carb with gumout but still not working...PLEASE HELP!

 

[Lou C]

Re: 4.3 OMC bogs down

Sounds like an electrical issue, the trim switch pulls a lot of current, which may result in the spark being not hot enough to make the engine run right. I would start with a check of the whole ignition system (points, condenser, cap, rotor, wires, spark plugs, etc. I also heard of something involving the ballast wire with this issue, do a search it may have been discussed here.

 

[stormin4]

Re: 4.3 OMC bogs down

Finally fixed the problem!! Wish I could say exactly what it was but I'm not 100% sure. Changed points, condensor, plugs and fuel filter. Discovered that alternator was not charging even though I was able to start the engine due to installing a fresh two-battery system at the beginning of this season. Replaced alternator and it ran a whole lot better but not quite right. Discovered two loose spark plug wires, popped them back on and now runs great again!