1995 Speedster 657 engine and rotary valve question

[skidooboy3]

I already posted a question about this but realized I posted it in the wrong area so I'm reposting here in the right spot. I'm a newbie with my first Sea doo. I bought a 1995 Speedster from a guy who bought it last year with one seized engine. He paid someone to rebuild the top end but he never installed it back in the boat. We wanted to check it out before installing it to make sure it was good and when we took the rotary valve cover off, we found the face on the case had a pretty deep circular groove. The groove is so perfect and centered it almost looked like it was intentional but we've never seen that before so we pulled the cover off the good engine and that one is smooth. I'm trying to figure out why someone would rebuild the top end when the case is bad so I'm just checking on here to get an opinion if it'll run like that or not.

I'm also wondering if all the 657 motors were the same. All the engine cases and rotary valve covers on ebay say they're from 1994 Sea Doo XP 650X. The part numbers aren't the same according to Sea Doo microfishe yet they look identical in the pictures. It looks like I can buy a case, cover, and valve plate for about $160 on ebay. Anyone know of a cheaper option or will these work?

 

[timmyboy76]

the 657 vs. 657X are NOT the same. The X has a 1mm higher deck height. BUT all the internals are the same...crank, pistons, rods..etc, but if you find a X case, then you need a X head, cylinders ARE the same.

As for the "deep groove". Does it go from "port to port" holes. If so, the nthat case is no good, unless you weld it up, the n"plane" it smooth. If its goes around the holes, then it'll work, just extra "pockets" for lubrication. What happened, with that kind of groove, is look inside the "port" holes of intake manifold, and tell me if you see a brass fitting on one side and not the other...

 

[skidooboy3]

Thanks for the information. This case is bad then because the groove is in the center of the ports. Both the brass injectors are in the ports. I'm starting to think I got fed a story on this one. I pulled the rest of the engine apart today and the top was all freshly painted and had a SBT sticker over the painting. Where the water jacket holes meet the base I can see dirt on the gaskets so this engine was definitely ran after it was rebuilt. So now we're guessing they had it rebuilt and dropped something in the intake when putting it together which wrecked the rotary valve and they decided it wasn't worth the work fixing it.

Oh well, I just ordered the new case, valve, and rotary valve plate off ebay for about $150 so it's not the end of the world. As long as I have your attention I have a couple other quick questions if you don't mind....

The small hoses on the oil injection pumps on both engines are cracked and rotted. If I just replace with other hoses can I reuse those crimps or are those crimps replaceable without going through a dealer?

Also what do you use on the exhaust joints for sealant where the clamps go? I see some orange residue at each joint.

Thanks very much for all your help!

 

[timmyboy76]

yup..just replaced those small lines on ski, work'n. You can re-use those clamps. Also, for line replacement, any hobby store, i used the "dubro" fuel line, perfect replacement, with the same clamps.

For sealant, use high temp sealant...head gasket sealant.

 

[skidooboy3]

Thank you very much for the info!