717 Crank Seal Blew Out. Replace seal or rebuild? (1996 GTi)

[risc]

I was running my new to me 1996 GTi in the water trying to figure out an engine bogging issue that only occurred in the water. I bought this ski in the winter for $1000, previous owner didn't have it for more than a year and said he bought it just for the trailer it came with and that it ran great when he took it out last summer. Compression is 117 and 119 (harbor freight gage). It idled great in and out of the water, I tore into the carbs only to find they were clean and looked to be rebuilt recently (didn't touch the needle and seat). The mixture screws were also set to spec. Disconnected the red wire on the rectifier, still bogged. Ran it for probably 30 minutes total over 2 days with the engine bogging condition until I noticed a lot of smoke in the bilge. Further inspection revealed some oil around the PTO side of the engine. Found a rubber ring along with a chunk of crank seal in the bilge (image 2). Turned over the engine and saw the crank seal sticking up past the PTO flywheel (image 1).

I am guessing I am in full rebuild territory for this engine? Is it worth trying to just pop a new crank seal in?

Was the bogging issue related to this crank seal leak/failure?

This is my first jetski and I was planning on running it for this summer to see how I like it before dumping money into a rebuild.

 

[mikidymac]

That engine has been apart before and got really hot.
Yes, you should take it completely apart and inspect everything.
No you can't pop in a new seal, cases have to be split.

If compression is correct it is toast.

Do not trust that the carbs or fuel system were done correctly either.

 

[risc]

Anything to look for specifically when tearing into it in regards to damage from its suspected overheated past?
I guess I'll plan on rebuilding carbs with genuine parts and setting/verifying pop-off along with a bottom and top-end rebuild. This seems like a lot of time and money to me, trying to decide if it's worth the effort.

 

[mikidymac]

Check pistons, rings and cylinders and crankshaft bearings.
A complete WSM gasket with seals is about $85 from PWC Muscle (Site Sponsor).

 

[risc]

Started tearing into the engine. Noticed a horizontal gouge (maybe a crack?) in one of the cylinders near the top. Also found the rotary valve and mating surfaces to be all grooved up. Is this rotary valve grooving normal for a well-used engine or should this be addressed?

 

[mikidymac]

That thing is nasty.

Only a machine shop will be able to tell you if they can bore that cylinder enough to clean up the gouge.

The cases and rotary cover are pretty worn and dirty but should be fine. I would change the little oil injection lines and get a new rotary valve.

Also looks like the might have been using the wrong oil so get the correct API-TC oil.

 

[risc]

Yes I am draining the oil tank which contains a blue oil and replacing with the SeaDoo mineral oil.

After pulling the PTO flywheel, there were no remains of the crank seal in the bore around the crank. I know I should split the case to at least inspect the bearings, but it looks like there would be nothing stopping me from tapping a new seal right into place with the cases together.

Is splitting more of a requirement to get the old seal out? I would like to just pop a seal in and get some light use this summer planning the full rebuild for winter.

 

[mikidymac]

Absolutely not!
These seals do not press in like a conventional seal.
The only way to install them is to split the cases and at that point you might as well do all the seals except the inner crank seals which are not DIY.