Carver Owners Forum

My 2000 396 aft cabin has twin 454 Mercruiser engines. This week the port engine would shudder and drop RPMs when brought up to about 3000 rpms or more.

I added fuel additive and changed the filter on that engine but the problem persisted. There was no issue with the engine below 3000 rpms. There is no issue with the starboard engine.

Any thoughts?

I see you note that you changed "the" filter, but did you change ALL the filters on the port engine? Usually there's more than one in line. There'd typically be a water/fuel separating filter, then a finer filter after that. There might also be a "high pressure" filter after the secondary fuel pump on some fuel injected engines.