1999 Seadoo GSX Ltd problem

[AllThingsWet]

Sure hope I posted this in the right spot. I could use some technical help.

Looking at buying a used 1999 Seadoo GSX Ltd from the original (gear-head) owner who is unknown to me. The motor has 135 hrs on it and has never been rebuilt. According to the owner he started having trouble with the machine about 6 yrs ago when he couldn't get the thing over 25 mph. He searched the internet and found reports of similar problems caused by a blockage in the cooling system. According to the owner the blockage causes the engine to reach maximum operating temperature prematurely and then power is somehow restricted. The owner tried to clear the apparent blockage but couldn't access certain areas so he gave up and parked the ski for the next 5 yrs. This past summer he pulled the thing out and (surprise) the problem was still there. Again he tried to flush the cooling passageways but no change in performance.

Any thoughts on cause and cost to repair?

MORE BACKGROUND: According to the owner, compression on all cylinders is good. The unit has been in fresh-water only (not sure that matters?). Apparently it has been stored in a heated garage every off-season until this year when it was moved to an unheated shed. (I still need to ask if he winterized it.) Lakes and waterways here are frozen so I can't test the ski. The asking price is reasonable but not if it needs more than about $500 in repairs, unless he's negotiable!

p.s. - I know a little something about engines in general but have absolutely NO experience with jet skis.

Thanks in advance!

 

[Minnetonka4me]

Blockage in the cooling system would yield a hot motor. It has to get super hot to make it bog/ not go fast.

Its possible that maybe the pipe got a crack in the waterjacket and all the water is flowing there and not to the motor. that would be the first thing...and while you have it off rebuild the carbs and change out the fuel lines.

If you can at least crank it over, start it, and check compression...that would be a plus. I dont know what their worth in CA, but in MN its worth about 3g in prime season. I'd say offer $1000-1500 if it has good compression; more for a trailer.

 

[Seadoobuddy]

Allthingswet - Welcome to the forum.

since you can't test run it. I would ask about winterizing like you mentioned and also feel around the whole block to see if any "bulges/cracks" can be felt. Crank it over to test compression. Bring a battery in case he doesn't have a good one. Don't jump it off a running car or truck.
If it won't crank then take out the plugs and try to move the pistons up & down to eliminate a possible seized motor.
check the impeller and wear ring. Check for gray tempo fuels lines, a 99 may not have them but check anyways.
Let us know what you find.

 

[AllThingsWet]

Thanks for the input...and the welcome.

It includes a trailer so I was thinking about $1500-2000. Though it seems like repairs can get expensive quickly (especially if the labor is hired) so that concerns me. The owner mentioned that, when the problem first occurred, he noticed the spray from the bleed outlets was much shorter just prior to the ski dropping off in speed. I assume this could be a sign of a cracked cooling line or blockage(?). But I wonder if he's recalling the sequence wrong. Isn't the length of the spray a function of engine speed and so when the engine slowed down the spray got shorter?

How much will it cost (roughly) to rebuild the carbs myself. I'm not familiar with "gray tempo fuel lines". Should they be replaced if found? I believe he has a compression gauge so I will definitely test for myself. (Throttle should be held wide open, correct?) Can I use a 12V battery from a 700 cc quad?

The owner told me that the wear ring needs replacing but mentioned nothing about the impeller. I will look, but is it fair to assume that if the wear ring needs replacing then the impeller likely does as well? Now that I think about it I don't recall if he actually said the engine speed fell off, or just his forward speed. I assume it was both but will double-check. I believe he said the drop in forward speed was fairly sudden so if it was caused by a problem in the impeller area I imagine it would have been very obvious to a gear-head.

I'll keep you posted, and thanks again!!

 

[Minnetonka4me]

If the pump is really trashed and there isnt much left of the wear ring, that can be a possible issue with getting enough pressure to cool the engine. usually if the wear ring is bad, so is the prop. Aftermarket wear rings can distort and get chewed up much easier.

Carb kits and needles and seats will run about $150, fuel lines are about $50 these days.

That battery will work for testing, just make sure its charged.

A trailer has a big range of value...a single super basic trailer is worth like $200, where as a nice deluxe aluminum is worth upwords of $600.

If the pipe is cracked its $100 + ship...but if the motor has to be torn down to get the blockage out (sand usually) you're talkin 5-700 if someone does it...and at that point if anything is wrong with the motor y would be a fool to put it back together w/o fixing it. See how the domino effect is happening?

 

[AllThingsWet]

I told the owner what I would be willing to pay if the engine ran and compression checked out okay. He declined so the search continues.

I didn't get the ski but I know a lot more than I did yesterday thanks to folks like you on this forum!

Cheers and happy holidays!

 

[Minnetonka4me]

Yup just move on...some people either want to find a sucker or they dont really want to sell it when a reasonable offer is declined.