Thread: Opinion on piston condition?
05-22-2011, 02:39 PM #1
- Join Date
- Mar 2011
Opinion on piston condition?
I have attached photos of the pistons from my 951. A little history on the motor. I bought the ski not running. The previous owner jump started the motor frying the MPEM. In hindsight I think the reason he had to jump start it is because it lean seized on the lake. Anyway I fixed the MPEM issues and rebuilt the carbs, and replaced the fuel lines and such. When I was working on it I noticed that the vacuum line for the RAVE circuit was not attached to the fitting on the motor (possible cause for the lean seizure in the first place?). Silly me I took it on the lake and I guess the extra friction from the original seizure caused it to seize again. Anyway the PTO piston is the one that seized and the nipple forthe RAVE circuit is directly under it. Do I need to be worried about contamination in the cases. I donít want to buy all the special tools necessary to split the cases unless it is absolutely necessary. Will a new set of pistons and a bore fix er up?
05-26-2011, 02:57 PM #2
I would just to a top-end on it. Since you didn't have a complete meltdown... the crank is probably OK.
BUT... you need to figure out why you had the lean run in the first place.
05-26-2011, 04:40 PM #3
Is that rust on the crank in pic 1? If yes it's on the bearings too.
Post a pic of the tops of the pistons. Looks very lean but piston wash will confirm.
ps. what "special tools"? a harmonic balancer puller is ~$12.
05-26-2011, 04:44 PM #4
Crank looks fine but the lean condition needs fixing. I would run the high adjustment on the pto at 1/4 turn. Check the injection system something caused it not to get oil or it wouldn't be that bad. Check the oil line fittings going into the manifolds with air to make sure there are no clogged up check valves. Check the oil pump by the manual.
05-27-2011, 12:52 AM #5
- Join Date
- Mar 2011
Thanks for the replies
No rust on the crank... There is some carbon there... thought maybe it was the result of blow by
I think the lean condition was from the disconected rave circut. The crankcase was open to the outside via the nipple the rave circut should have been conected too. From what I have read those motors can lean seize from leaky crank seals. That nipple would let a lot more air in the case than a leaky seal.
Will check the injection system while the motors out.
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