Need help blown piston

[Philip Clemmons]

I'd agree it looks like detonation. I also agree with Blue.....front was looks good to rich, not lean. That said, the rear could have an issue by itself, but not likely since the front failed before too.

Squish is an important part if this equation, as is octane. Heavier boats are exponentially harder on pistons because its more load, and very easy to hold it there. Timing could be off as well. Never assume anything is right until you verify it to be correct. First rule of troubleshooting

 

[sxrchris]

Verified stock timing, or "I set it stock" timing ?

You're guess is as good as mine haha

 

[sxrchris]

I'm a kawasaki guy so this is all new to me! 62X...T..701...760.. blaahh blaahh just give me a big pin 800 and I'm good. Anyways I think its fixed. Piston was changed, new head gasket and they put a different head on. Originally they had the 62T on, now stock 64. That could have been the main issue idk.