Lean piston damage? 1999 Seadoo GSX RFI

[Nmelche]

Does this piston damage look like it was from running too lean? Thanks!

 

[mikidymac]

It is hard to say with all the mechanical damage as something really bounce around that cylinder.
I carefully pull the piston pin and count all the loose piston pin needle bearings as those can cause this damage also.

As far as the piston wash it does look lean.

 

[Nmelche]

It is hard to say with all the mechanical damage as something really bounce around that cylinder.
I carefully pull the piston pin and count all the loose piston pin needle bearings as those can cause this damage also.

As far as the piston wash it does look lean.
View attachment 56856

Thanks for the response. Haven’t had the chance to remove the piston yet but will in the next few days and will count the needle bearings. I’ve seen that diagram before and was basing my lean guess off of it. If you look up lean detonation, it looks similar to my piston. I’m thinking that’s more likely than something actually banging around in there. Could be wrong though.

 

[Boyd12]

What does the inside of the head look like? I am no expert but "something actually banging around in there" is where I would put my money! Good luck!

 

[Nmelche]

What does the inside of the head look like? I am no expert but "something actually banging around in there" is where I would put my money! Good luck!

Looks pretty good actually. Very minor scoring. Nothing you can feel with your fingernail. Don’t think anything was banging around after taking apart the whole top end. I’ve been chasing a hesitation problem and a low top rpm problem before this happened. That’s why I think it ran lean while I was testing a “fix”.