Engine very rough at low rpms - why?

[Compass790]

Originally Posted by Ostinato

It’ll be a week before I can get to the injectors on mine. I’ll let everyone what happens. Cautiously hopeful at this point

FWIW the vid was a great help. Worth a thousand words to me any way.
Good luck with tracking it down.

[Ostinato]

Unfortunately it was not the injectors. Moving on to the pressure plate.

[galynd]

Originally Posted by Ostinato

Unfortunately it was not the injectors. Moving on to the pressure plate.

Bummer. Thanks for the update. I'll be on mine tomorrow. Please continue the updates.

[FPNC]

Check the engine mounts. You can have good alignment and bad mounts that will cause this. They may even look good but be bad. You will have to pickup the engine to tell. It is important to make sure each mount is supporting the (relatively) same amount of weight. If mounts are loaded heavy on the diagonal they will allow the engine to shake like this. Raise your idle speed.

[Ostinato]

It was the dampening/pressure plate. No question. The new issue is why did it go in less the 700 hours on the starboard engine and why did port engine dampening plate go even quicker a year ago with about 200 hours on it?


These are robust plates by Centa. Fortunately they can be rebuilt in the states but it's still disruptive and expensive.

[DeepFrz]

Originally Posted by Ostinato

It was the dampening/pressure plate. No question. The new issue is why did it go in less the 700 hours on the starboard engine and why did port engine dampening plate go even quicker a year ago with about 200 hours on it?


These are robust plates by Centa. Fortunately they can be rebuilt in the states but it's still disruptive and expensive.

Thank for the update.
We would love to see pictures of the failed plates.

[Compass790]

Originally Posted by Ostinato

It was the dampening/pressure plate. No question. The new issue is why did it go in less the 700 hours on the starboard engine and why did port engine dampening plate go even quicker a year ago with about 200 hours on it?


These are robust plates by Centa. Fortunately they can be rebuilt in the states but it's still disruptive and expensive.

Yes very good question "why did they fail so early?" You never said you'd had them replaced fairly recently which may have been a diagnostic clue. I'd be suspecting installation errors without knowing those engines.
Bit of a worry if you cannot find cause of failure. Another vote for pics of failed plates please.
Bummer it wasn't the injectors
thanks for updates

[galynd]

Originally Posted by Ostinato

It was the dampening/pressure plate. No question. The new issue is why did it go in less the 700 hours on the starboard engine and why did port engine dampening plate go even quicker a year ago with about 200 hours on it?


These are robust plates by Centa. Fortunately they can be rebuilt in the states but it's still disruptive and expensive.

Thank you very much for the updates.

[galynd]

Ostinato,
One questions.... Once it was opened up were there visible signs of wear, such as a broken spring, etc.?

Thanks again,
Greg.

[Ostinato]

These use rubber bushings so no broken springs but yes the rubber cushioning inner ring which the spline enters was loose showing that rubber has worn. Here are some pictures of the defective part and how it looks when installed. Compared to the spring type it is huge.


I've seen these rubber type on other boats with over 2000 hours and no sign of wear. Previously I used the spring type on this boat with different sail drives. I've gotten anywhere from 400 hours to 2000 hours with them.


None of the professionals I've talked to seem to have an answer except that this kind of event happens. The lucky thing is that they can be rebuilt in the USA. I'll be carrying a spare you can be sure of that.

[Compass790]

Thanks for pics & up date. If they normally last in excess of 2000hrs I'd suspect some kind of alignment issue if there was no manufacturing defect or installer error.
But you need someone familiar with the unit to chime in.
Best of luck finding the cause.