1995 Sea Doo XP Rebuild Project

[Matthew Sean]

Hi,
I just bought a 1995 Sea Doo 720 XP with the motor not running. The rear piston seems chipped. There is also a tune pipe installed on the motor. The sellor told me he had the pipe installed, tried the PWC and found it had no power. Hauled off the motor head (due to low compression of 60 pounds) and saw the piston was chipped? Now I have the disassembled motor and was wondering if any of you have an idea as to a possible connection between the tune pipe and a burnt piston? Before I change the piston, I'm wondering if I should change the pipe for stock pipe? This would imply also changing the manifold to stock. Anything specific to look-out for except adjusting the carbs rich when installing a tune pipe? Changing a piston?

 

[bell99man]

Failure not likely due to the pipe. I would look pretty hard at the fuel delivery system. Running lean will cause pitting of the pistons and a number overheat failures. Check for grey fuel lines and clogged screens in the carbs. If yours are still grey, replace asap. With the duel carbs, one could be more clogged and cause one piston to go quicker. Read the 2 stroke tech section.

 

[Matthew Sean]

Thanks for the cues. Greatly appreciated. I got the PTO cylinder off this PM. What a time it took to unscrew the allen bolt holding the pipe to the manufold! Had to work at a snails pace given the lack of space. Grinded my allen key shorter on each end to work at it. The piston is definetly cooked on the manifold side with the rings melted into the piston. Now my question is this: can I change this one piston without taking-off the mag end cylinder? Do I really need the special puller mentionned in the motor manual to remove the piston pin puller? Any experience anyone?

 

[bell99man]

You may want to re-ask this over in the 2-stroke section.

I have actually not had to break one down, but I would bet the tool will make it infinitely easier. If you managed to get the circlip out, it seems like you just need to tap out the wrist pin. As far as the repair goes, I would do both pistons at the same time. You really need to look at both for damage, and if you only do one and the other is borderline, you will be right back in the shop.

Once you have the motor back together, dive into those carbs and the whole fuel system. I'd check out the oil system as well while I had stuff out of the way.

Kevin

 

[Matthew Sean]

Much appreciated Kevin. I'll make sure to follow your precious instructions. Matthew

 

[bell99man]

If that is sarcasm, I'm sorry. I was just trying too help. If you think I'm wasting your time, don't follow it. It's only advice. But seriously, more people read the 2 stroke section and you will get more help from the mechanics. Good luck and I hope you get it running soon.

Kevin

 

[Matthew Sean]

Hi Kevin, that was an honest thank you. No sarcasm. I really appreciate your leads. Regards. Matt

 

[bell99man]

Hard to tell on a forum. Sorry and thank you.