Volvo Penta 5.0 GXI-B stuttering and blowing ignition fuse

[MTEsCobalt]

Dealer has been unable to solve my problem, spent lots of $$. Problem is that, when under load, especially pulling a skier, upon giving full throttle the engine stutters and eventually blows ignition fuse. Thought it was a gas problem but had filters changed, gas checked and fuel system checked by dealer. They've also checked all elec system and cannot find source of the problem. When problem is at it's worst, if I have it out of gear, can rev at high RPMs with no issue, sounds great. As soon as I put it in gear and go full throttle it starts to kick out and blows fuse. Really frustrating. Any help greatly appreciated. Owned boat for 5 yrs, never had a mechanical problem, well maintained. Haven't made any changes, problem appeared out of the blue. Thanks.

 

[rodbolt]

Re: Volvo Penta 5.0 GXI-B stuttering and blowing ignition fuse

try borrowing a seperate ign harness. this will isolate anything under the dash and any hull rigging issues.
if it still blows ign fuses its on the engine,if not its in the hull rigging.
if its on the engine look carefully at all the wiring,especially purple colored ones.
many things power up by the ign fuse.
the engine ECU,the alarm system,load should not make much difference in current draw other than possibly longer injector duration.
what is the system charging voltage?