951 XP - Rebuild - investigation into the causes of failure

[bubels]

Hi,

Last sumer my xp ltd died.
We took it that day as an extra jetski. It had a new battery. It started easily on the trailer. When I turned it off in the water it had trouble starting.

It eventually died at full speed.

Finally it was time to fix it.

A picture of the damage is below.




The problem is with piston number 2 - stern. Rings are fused into the piston.

I would like to understand how the failure occurred.

Please advise?

 

[mikidymac]

First thing that should have been done was pressure test the engine. This would have shown if there was an air leak causing it to go lean and seize.

Just guessing from the way it stopped and the damage you had a fuel starvation issue (carbs or fuel system) or an oil starvation issue (broken oil injection line from oil pump to intake manifold) and it seized.
You will need to rebuild with refurbished crank, balancer shaft, reeds, bore top-end and new oversized pistons and rings as well as finding out the cause or it will happen again.