Fuji 750 rebuild first time rebuild

**Jlabe121** · 11-28-2020, 06:46 PM

How’s it going everybody. I bought two 90’s Polaris jet skis and it came with a motor that has a piston that look like it exploded with that being said I have always wanted to rebuild a motor and it would be nice to have a back up for one of my 750 slt. How can I make sure the crank is in good condition and still in index can that be done with the motor torn down? Also I’m waiting for my flywheel puller to get into the crank case do the piston arms come off or can it be replaced? It’s scuffed up from the damaged piston. Any advice and info on rebuild kits would be great. Also what do you guys think of the other pistons or should I do all three? Thanks for any help!

**casey67** · 11-29-2020, 11:13 AM

Welcome to GreenHulk.

The crankshaft is pressed together. A complete crankshaft rebuild is needed, it looks like bearings from the crankshaft found their way to the top of the piston. At that point the other 2 cylinders should be addressed.

There is alot of rebuild info on this site.

**BlueFishCrisis** · 11-29-2020, 05:38 PM

Full rebuild here: http://greenhulk.net/forums/showthread.php?t=193805

**BlueFishCrisis** · 11-29-2020, 05:40 PM

Looks like full rebuild. Probably crank too....

Carbs need rebuild kits as well, usually... All fuel lines should be updated.

**Jlabe121** · 11-29-2020, 06:35 PM

Thanks for the info hopefully the flywheel puller will get here tomorrow so I can tear the rest down.

**Jlabe121** · 11-30-2020, 06:28 PM

I got the crankcase open and all I found damaged was the seal. Once I got all the pieces of the piston out everything spins nice and freely. The ball bearings are all in place that I can see. The Pto rod is scuffed up where the wrist pin goes in but thats all I can see. What is the next step do I need to send the crankshaft out and make sure its good and does the scuffed rod need to be replaced or will it be ok. Any help is much appreciated.

**xlint89** · 11-30-2020, 10:07 PM

Unfortunately, just that one rod would make me want a whole new/rebuilt crank. You can try to save a few bucks and replace just that one, but it wouldn't be worth it to me. That's just my opinion.

**Myself** · 12-01-2020, 12:54 PM

My wife's old GP1200 was very similarly damaged and after cleaning the crank was OK. Use something like a water bottle with a hole drilled in the lid and slowly pour gas over every bearing while rotating them. That will flush the debris out of the bearings. Pay close attention to the lower rod bearing on the beat up one. And spin and inspect the thrust washers next to the rod. Then try to get a straightedge next to that rod to check it. And pull the rod away from the crank feeling for play.