rebuilding 951cc first time need advice

[bradw18]

well this is my second thread. i decided to create another one becuase the name ( finally got her running) is a little misleading. now shes blowed up!!!! taking her out was the easy part. figuring out what happend is the hard part. i bought the ski for 1000 shes a gtx 1999 with a 951 engine. before i started it i tested compression both 130. cleaned carbs installed new rebuild kits and took off. evey 2-3 mins i shut her down and checked the plugs. one was rich one was lean. each time i did a little adjusting. on the last pull i did she shut down and was very hard to start back to make it to trailer. ( never got more then a few 100 from the trailer haha. ) i figured it was just the carbs again so i didnt think much about it. pulled it on the trailer and blamed in on the carbs again. i wasnt for sure what the pop off pressure was in the carbs. the new rebuilt kits came with shinny springs that put the pop off pressure between 40-45 on one and 35-40 on the other. i replaced the springs with the old springs and got the pop off pressure back to were it should be. decided to do a compression test one last time before i installed carbs and this is what i found.....

 

[bradw18]

i didnt get to ride it for more then 4 mins tops and each time was stoping every few pulls and checking plugs. think some of the damage happend before i owned it? has 190 hrs im thinking on deleting the oil pump injection. the bottom end spins free still with no catches or rough spots. heres the rebuild kit i bought

 

[SabrToothSqrl]

200 hours is the average for a 951. if you didn't make any changes, then yes this damage was most likely there. You could have pulled the RAVEs and used a flashlight to look inside the cylinders.

you should also put in a new crank, or have a shop build you a 951 w/a warranty.

a fresh top end with all new parts / power may have you doing all this all over if / when that crank goes. (don't ask me how I know)

also, don't remove the oil pump. it works very well.

 

[bradw18]

to late on the oil part. id much rather premix my own oil... my oil injection on my bennington pontoon boat went out too.. could of all been prevented with just premix. hot rod cranks are a little expensive. there is no rod play in the rods. how much more work am i looking at when putting a crank in? im gonna be jumping waves and riding her hard when i do take it out. i heard something about a good remain seadoo crank whats the part number on it any idea?

 

[SabrToothSqrl]

the oil pump on these is very reliable, but if that's what you want.

I don't know, you can check 'brp parts' for the part number of anything on these. just google it.

I'd just hate to see you have to take it all apart again if the crank fails.

 

[- BiRkS_]

I'm rebuilding a 951 right now too, decided to split the case and see what was going on, bearings, etc. Sure enough there was water in the case, and although the crank turned smooth and without the bearings growling... the fact it had water in it makes it worth going the extra mile. That way its done once, done right, and ready to go for the rest of the ski's life. A set of used cases is probably worth more than the new crank, and gasket set.