96 seadoo xp 787 broken piston on pto side

[xp787]

I have a 96 xp 787 I was riding it and parked it at the dock the went to start it to put on the trailer and it started the just died. When I got it home and took the engine apart and the pto side piston had chunks missing out of piston. Im gona put a new piston in but I just want to know why this happened before I put the piston in a nd have happen again.

 

[Dr Honda]

It looks like it was chipped away. Is the electrode of the spark plug busted off?

 

[xp787]

The electrode looks fine and the head combustion chamber looks fine and theres only little dings. The top ring is bent and when I turn it over it locks going down and i can see were it hits in the jug the bent part is hitting the intake port of the jug.

 

[my787]

could be detonation or loss of oil

 

[Dr Honda]

could be detonation or loss of oil

Detonation shows up in the middle of the piston, and lack of oil NORMALLY shows up as a melted skirt.


That looks fractured. The only thing I can think of is that the ring got caught in a port, and it busted the top of the piston.

Did you get water into the engine? If you did... the ring could have rusted, and stuck to the cyl wall, and pulled enough to break the piston.


At this point, it may be hard to tell. Take the engine apart, and make sure the ports are properly chamfered, and the cyl walls are smooth.

 

[xp787]

thanks for the info i found out that there was a lack of oil because the other cylinder had some aluminum melted to the cylinder wall so i decided just to get new jugs and pistons and new oil pump

 

[gsxgtxman]

U may not need an oil pump! Have you been mixing oils? Try bleeding the pump before u remove it! It might have clogged up? Mixing oils can cause gum up in the lines not allowing oil to flow?