1997 GP760 Wave Runner scored pistons and cylinders

[homelite]

Help from an experienced 2 stroke mechanic.

Hello. I'm an automotive master tech. I need someone's help as I do not deal with 2 stroke issues very often at all! I had this jet ski for years. No issues. This weekend it quit. No restart. Cranked like not much compression which was true. 35psi in each cyl. Pulled the head hoping to find a blown gasket. I have scored pistons and walls/broken rings etc. So...why? I have it apart and see these kits online for the jug/pistons/gaskets for roughly $500 t0 $600. I have no issue buying them and fixing it, but the scary thing to me is WHY? Is it:

1. The 87 octane over time? Book says min 86 octane
2. Too lean? If so, how to fix?
3. cheap oil? I use the proper oil in the book and I use name brands

It ran fine until it quit and it fried both cylinders. Any help from experts on here would be greatly appreciated.



Thanks

 

[Scott Danforth]

Too lean, look at your fuel system

 

[Scott06]

Agreed running lean and detonating will hammer the rings and pistons to death and ruing the motor

Would be looking for fuel system contamination, proper fuel pressure, and dirty carbs

 

[racerone]

Automatic oil injection ?-----If so have a good look and test and inspect it.