Damaged #5 and #6 cylinder

[Gmicsky]

I recently purchased a 2004 Monterey 265 with a Volvo Penta 5.7 GXI-F - 500 hours. This was the first tank of ethenol fuel to be run through the boat @ 86 octane.
Second trip out I could not get over 3000 RPM/ 15 mph and motor was popping. Heard a whining or squeal that I thought was an idler pully because it was not a constant noise.
Mechanic discovered damage to the #5 and #6 cylinder. Said the cylinders over-heated at some point to cause the damage. Damage includes Piston, cylinder is scored and valves are tuliped. 2 Unrelated mechanics suspected blocked injector causing a lean fuel mixture thus damaging the motor. I have also heard from other people ideas like wrong prop to paint clogging the injector from the fuel pump.
Has anyone experience such a problem?

 

[Bondo]

Re: Damaged #5 and #6 cylinder

I recently purchased a 2004 Monterey 265 with a Volvo Penta 5.7 GXI-F - 500 hours. This was the first tank of ethenol fuel to be run through the boat @ 86 octane.
Second trip out I could not get over 3000 RPM/ 15 mph and motor was popping. Heard a whining or squeal that I thought was an idler pully because it was not a constant noise.
Mechanic discovered damage to the #5 and #6 cylinder. Said the cylinders over-heated at some point to cause the damage. Damage includes Piston, cylinder is scored and valves are tuliped. 2 Unrelated mechanics suspected blocked injector causing a lean fuel mixture thus damaging the motor. I have also heard from other people ideas like wrong prop to paint clogging the injector from the fuel pump.
Has anyone experience such a problem?

Ayuh,.... Welcome Aboard,... Why didn't ya turn back to the dock,..??

What did the contents of the fuel filters reveal,..??

Has any forensic diagnosis been done,..??

 

[Gmicsky]

Re: Damaged #5 and #6 cylinder

Ayuh,.... Welcome Aboard,... Why didn't ya turn back to the dock,..??

What did the contents of the fuel filters reveal,..??

Has any forensic diagnosis been done,..??

Yes, did return back to the marina. Nursed it back as soon as I realized there was a problem. Just talked to the mechanic today and he said injector screens did not show anything unusual. He cleaned the screens and will also replace the fuel pump. Filters showed no dirt or water. Two other and different marinas suggested that the ethanol is loosening paint inside the fuel pump causing injector problems. Sounds like this could be a common problem but I am not seeing many posts on the forums to verify their suggestion.
The only forensic diagnosis completed has been having two different mechanics look at the motor. Both verified that the motor was junk and was caused by overheating of the two cylinders. I just don?t know what could have occurred that could cause that type of damage so quickly.

 

[Maclin]

Re: Damaged #5 and #6 cylinder

I suspect you just found out why the boat was for sale. Even though it is a possibility, I do not think that damage happened all on one trip.