Volvo Penta 5.7L dies under load

[radsol]

I have a 2004 Mustang Sportscruiser 38ft with 2 X Volvo Penta 5.7 litre 280 HP engines. The starboard engine developed a problem about 8 months ago where it would die under load, engine would then rev up & down even when throttle was at idle. Mechanic swapped the coil between port & starboard engines & the problem went away but it is now happening again. Knock sensor, crank position sensor have been replaced, fuel pump & fuel system has been checked. ECM has been swapped.
Anyone had anything similar with Volvo Penta inboard? Any help would be sincerely appreciated.

[Chimo]

radsol

Ring 0413 587 273 and ask your question.

Cheers
Chimo

[GBC]

yep - two weeks ago.
Get to almost on the plane then start pigrooting, slow back down and commence backfiring until it all catches up with itself.

It's sitting on the hard at East Coast marina at the moment waiting for the mechanic to show up (gear shift failure).

I will follow up when he gives his diagnosis.

I think old fuel is going to have a fair bit to do with it along with something else fairly minor.