Running on 1.5 cylinders

[SuperJet-Dave]

Put in new Pro X pistons. Looks great compared to the mess I had. 180 psi in each cylinder. Motor starts and runs on one cylinder. Same for each cylinder! Yeah!
Thanks everyone for all the help on this one.

... and it is back to running GREAT in the water. Probably only a few more wetsuit rides left this season, but nice to have it running 100% again

 

[Quinc]

Seems like even the "good" piston had blow by. Bores or Rings must have been really worn. And that Piston with the missing skirts was slapping something fierce.

Post #25 by Quinc was spot on diagnosis.

 

[SuperJet-Dave]

LOL

Do need to mention that OP's 10% (15+ psi) allowable delta in compression readings seems excessive.

5 psi max allowable difference is the Rule Of Thumb I've always heard for PWC two-stroke engines.

Agreed. That is what I have always gone by as well. Did not mean to indicate that 10% diff is acceptable earlier in the thread.