770 Crank Seals

[Quantum]

My 1998 770 was submerged and has never been the same. (The user actually tried to crank the machine when it was flooded!) I pulled the engine today and opened the crankcase and have a single question: are there supposed to be two C rings (Part#3003-359) in the race? There's only one, the top (case) in my machine. Thanks! (BTW, a top end rebuild is needed on the engine, too.)

[dank]

Re: 770 Crank Seals

Normaly trying to start the engine after it is flooded won't hurt the engine unless it bends/breaks a rod or pushes the reed pedal back threw the cage and sometimes it will crack a starter drive gear tooth off.

Why do you need a top end now? If the water sat in the engine then you need more than the top end rebuild.

[Technical Support]

Re: 770 Crank Seals

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[Quantum]

Re: 770 Crank Seals

Thanks for the responses!

The pistons are scored, not bad but clearly scored. Sleeves are smooth. I had the engine checked by a Arctic Cat mechanic and he reported "low compression" without any numbers. He left the head off so I can't check it myself...guess I should have before taking it in. The head gasket was in okay shape. (Needs to be replaced now, of course, when I reassemble.) Seems like a good time to replace some parts since I've got it out and on my bench.

I've been able to run ski but it's very rough and hard to start...won't idle either. The reeds look fair, but I may put some fiberglass replacements in. Any thoughts on these?

The case was wet when I opened it but the seals all looked good. I have not removed the crank from the bottom cover.

I'm anxious to put the boat back in the water. Up here in Wisconsin, we don't have many days left! Thanks again fro the responses.

[dank]

Re: 770 Crank Seals

What was the compression befoer you took it apart?

Fiber glass reeds don't last that long. Carbon fiber are better but the stock reeds last a very long time.

If you want to try it and the pistons and cylinder are within specs I would do this:

1. Replace the crank seals
2. Hone the cylinder a little
3. Put the stock pistons back in with new rings.
4. Rebuild the carb/s.
5. Clean the fuel tank and use fresh fuel.
6. Install and oil block off kit.

If you don't want to risk it or the engine is out of specs then I would get an engine from SBT and do steps 4,5, and 6. After all it is a ten year old engine so you never know how long the crank bearings will hold up.

[Quantum]

Re: 770 Crank Seals

Thanks for this advice...I will take it and see how things turn out. Looks like the SBT rebuilts are a good option but I'll check out the more economical route first.