What happend to my motor??

[712bobbyjr]

This happend a while ago but never got time to look at it. The pistons are burnt up and there is pieces missing from the piston and the cylinders are scored. Took it to the shop and they said the number 2 & 3 cylinders were scored and a piece of the #3 cylinder was missing. I thought that maybe the oil injector went out but it appears to me that the cylinders have sufficient amounts of oil on them... Was it the Gas? I remember when we went out we put the highest octane available in which I though was 91. The oil I put in Exceded the requirements by the motor. I did not have the boat long before this happend, maybe 8 months. I bought it used. Could this have been a problem that occured long before i bought it.. It ran great when i bought it. Any opinions would help lots on what I have to fix and how this would have happend.. Thank you so much!

I cant upload and pics for some reason.

[boscoe99]

What is the model of the motor?

Is it an F115 or F150?

[rodbolt17]

think son think.
if you cant do some googling.
key word piston detonation or piston erosion.

mostly 2 common reasons, incorrect ign timing at WOT
POR the most common, lean air to fuel mix at or near WOT.

overpropping comes in as a close thired.
that you found it,sucks.
but its actaually common with folks that just bought a a boat/motor.
typically oil issues show up as bearing failures.
piston failures are 95% fuel issues.

[TownsendsFJR1300]

What is the model of the motor?

Is it an F115 or F150?

He mentioned oil injected, so a two stroke..

Re the fix, (besides needing a year, model, HP), what part of the cylinder cracked, the lower end, by the ports? If its cracked, you can't re-bore and I don't think if you can get it re-sleeved.

Re pic's, upload to "Photobucket", then copy and paste the img code here on a post here, it'll show up full size..