787 pumping oil

[davetammy]

I have a 96 xp that I purchased from a guy who said he thought the starter was bad,got it home and pulled the plugs out and it turned over fine but pumped a bunch of oil out of #2,did a comp test on #1 it was 150 #2 hit 185 after only a few turns so I stoped and pluged the oil pump lines and tried 7 more times but its still pumping oil(this was just with the starter) could my rotery valve be way out of clearance or is there a internal problem? [img]graemlins/cwm3.gif[/img]

[ScreaminXP]

He may have thought it was the starter, but it sounds to me like it was hydro-locking from all the oil in the cylinder. It will continue to pump oil out of that cylinder until it is all out from the lower crankcase. How it is getting there is the problem.
One possibility is a bad internal seal which is letting the oil where the rotary valve gear sits leak into the crankcase on that cylinder.
The other possibility is oil leaking down through a check valve in the brass fitting on the rotary valve cover. (the small oil lines connect to them) They keep oil from gravity-feeding into the crankcase.
It's probably the internal seal, but if you take off the carbs and find a lot of oil sitting on top of the rotary valve on that cylinder, you may have found the problem. (check valve)
There are a lot of knowledgable people on this forum who may have more insight, so of course get a second opinion. I've only been wrenching on seadoos for 2 years now, but I'm pretty sure thats the problem.

[John Kubiak]

1996 was an "iffy" year for Sea-Doo 800 (787) engines, as far as sealing was concerned. You are correct on the possibility of the internal crank seals for the rotary valve shaft chamber. This is fairly common, and is simple to test for.

I have also witnessed several 1996 units that did not have a snap ring to hold the rotary valve shaft seal into the crankcase.

The other possibility is that the loctite 518 flange sealant used on the case halves has failed.

I would start with the pressure test of the rotary valve shaft seals. Pay attention to where the air is leaking out, although you know the leak is in the #2 cylinder, you may be able to discern if it is an oil seal breach or a crankcase sealant failure.

You can e-mail me with any questions you may have.
skitech@tampabay.rr.com

[davetammy]

removed rotary cover and turned engine over and there is oil shooting out off the crank out the rear intake port so I took the head off ,everything there looks great. Is there a chance the case seal is bad if so is it a job a normal mechanic could do?Could it have a bad cylinder?

[Bill O'Neal]

Dave,
Sounds like the motor and the crankshaft need to be disassembled and have the seals replaced. The best bet would be to buy a rebuilt crankshaft from SBT and install it. It will come with new seals. There probably isn't anything wrong with the clyinder, and if there was, it would not cause this type problem.

[davetammy]

are these seals one piece seals that are pressed on with the crank or two piece that fit into the case?Is it hard to get the halfs sealed back together?

[Bryan Glynn]

They are integral as part of the crank - you cannot do it at home.