1996 POLARIS 780 SLT

[RPTM]

I just purchased 2 1996 Polaris 780 SLT skis.
One of the skis has been checked and #1 & 2 pistons have holes burned in them. I was told by a PWC shop mechanic that this is due to the carbs being dirty and the fuel mixture was too lean. Have you had any experience with this issue? Does this sound reasonable?
Thank you,
Ronnie
* This is a follow-up to the problem listed above. I had the pistons replaced and the carbs cleaned and put in new spec plugs.
I have taken the ski out 3 times since repaired - a total of 5 hours run time. Using the brake-in procedure of minimizing idle and full throttle time. The performance is excellent. Rpm tops out @ 6400, response out of the hole is good and it idles fine. The only question I have is: There is an unsteady running zone between 4100 and 5000 rpm, its steady below and above this range. Is this standard for this engine?
Ronnie

[ August 25, 2003, 09:59 AM: Message edited by: RPTM ]

[polarisguru]

2 holed pistons sounds like a crankshaft out of index or water in the fuel. Improper heat range spark plugs and gap will also cause this. If it was lean, from carburation, then the sides of the piston will be scored also, and not just a hole in the top of the piston. If it was water in the gas or chamber, they will normally burn a groove in the top of the piston straight towards the exhaust port. Most likely its a deeper internal problem then easily diagnosed. :D

[ August 15, 2003, 06:05 PM: Message edited by: polarisguru ]