Power Problem

[Viscount]

I have 2 x AD31b - 290DPs. Earlier this year, one has developed a lack of power to the extent that when warmed up will not exceed 1,200RPM under load. Air and fuel filters all changed with no dice. Boat been out of water, all the usual done but also drives removed and checked over, no issues. Will now try to post a video (please make sure sound is on) demonstrating what happens when throttle applied in gear tied up at pontoon.

 

[spannerman]

That knocking is worrying, is it blowing hard if you remove the oil filler cap? I would try slackening each injector pipe in turn to see if the knock is on one particular cylinder. It doesn’t sound good from the video clip and needs investigating.

 

[Viscount]

Thanks for your reply. She's out the water at the moment but should be going back in this week. I will update the thread once I've tried what you've suggested.

 

[Viscount]

Finally got a resolution to this late last year; it was a burnt inlet valve. Head taken off, repaired and replaced. All is well again now. Happy New Year all.

 

[spannerman]

Thats good it wasn’t a bigger problem, have a good season.