Cummins all of a sudden wont hit rated RPM

[bud37]

Qr Bbpost Newbie question: how does one engine "hold the other engine back" from making full power in this situation? Assuming no synchronizer between the two engines.

Qr Bbpost From my limited knowledge of marine diesels, it may just be that one engine is creating the problem, there by holding the other back.......now that said, you did say this was an all of a sudden occurrence.....so consider anything just recently done on board.

I can say, if I had a marine diesel powered boat, the first thing , I would join Boatdiesel forums.

I will try to explain ,given the info in this case, simply, if one engine is down on power for some reason then it will not allow the boat to attain it's full speed thereby keeping the the wide open throttle rpm of both sides down below max rated.

I will add that in cases like this it may take a skilled diesel mechanic to go thru the engine systems to realize what is happening after ruling out the hull and props.....he did say it was sudden, but crossing off possibilities in some order is good practice.

[km1125]

Qr Bbpost Newbie question: how does one engine "hold the other engine back" from making full power in this situation? Assuming no synchronizer between the two engines.

Qr Bbpost From my limited knowledge of marine diesels, it may just be that one engine is creating the problem, there by holding the other back.......now that said, you did say this was an all of a sudden occurrence.....so consider anything just recently done on board.

I can say, if I had a marine diesel powered boat, the first thing , I would join Boatdiesel forums.

Because of the "bad" engine not contributing power, it's abdicating all the weight and drag of the whole boat to the "good" engine. The boat will not perform with only one "good" engine so that engine will never get to its rated RPM.

EDIT: OOPS! Didn't see Bud's response before I posted mine!

[Midnightsun]

Just try getting on plane with one engine for the heck of it, no way will it acheive maximum RPM, lucky if you get 2/3 of it a best and you will never get on plane by the way. Same goes for a poorly tuned engine or issue with an engine as without full available power from both, the good one is "held back" and will not achieve max rpm. Make sense?

[Midnightsun]

We are too quick on the draw here.