99’ Seadoo sitting for 4 years.

Joined
Apr 16, 2018
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Omaha, Nebraska.
#1
So i just acquired a pair of Sea-doo Jet skis from a family friend, but they haven’t been ran for roughly 4 years. I asked if they had been winterized before storing and they hadn’t. I’m looking to have these things running by summer and want to know the steps I should go through to have them running smoothly again.
1999 Seadoo GTI
1998 Seafoo GTX
Thanks, any advice or tips appreciated.
 
Joined
Mar 9, 2009
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374
Location
Ontario, Canada
#3
I went through this same thing for a friend but with a modified X2. The biggest concern I had was the condition of the crank. It wasn't winterized as well, and with no storage fog on the bearings they had accumulated condensation rusting the crank almost solid. Once I dove into it a little further I also found that water had somehow managed to seep through the pipe and accumulate in the manifold just enough to rust up the rings and form ice around exhaust port. That was the end of that engine. Full dismantling and part out. I would say to try and hand roll the engine by the coupler with the plugs out first to feel/listen for bad bearings or rings. Also, the old Sea•Doo engines were famous for worn out rotary valve seals and would leak injection oil into the base, if they have been leaking during storage, you could be into dry rusty/seized rotary shaft parts. I don't know if they used bearings or bushings there but certainly an area to be concerned with as well.
 
Joined
Jan 28, 2018
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Location
California
#4
If the rotary seals were leaking they would save the crank. Most of them leaked from using the wrong TCW-3 oil and not the correct API-TC oil. IF it turns over by hand it might be ok. Many old seadoo's are fine after you get the oil out that seeped through the crank seals. Some people will install a ball valve on the rotary oil line so it doesn't leak when sitting for long periods of time instead of replacing the crank.
 
Joined
Mar 9, 2009
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Location
Ontario, Canada
#5
If the rotary seals were leaking they would save the crank
Noooo, I wouldn't think of it like that. There is only so much oil in there to satisfy the needs of rotary shaft, it's definitely not enough to fill the crancase. Without the injector pumping the oil there is no flow and the premix does not contain any cling properties for prolonged storage.
 
Joined
Jan 28, 2018
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27
Location
California
#6
If the rotary seals were leaking they would save the crank
Noooo, I wouldn't think of it like that. There is only so much oil in there to satisfy the needs of rotary shaft, it's definitely not enough to fill the crancase. Without the injector pumping the oil there is no flow and the premix does not contain any cling properties for prolonged storage.
I think you have it wrong. On a seadoo it’s the inner crank seals that slowly seep oil into the crankcase when they get old. The oil tank is higher than the engine so it can dump a gallon of oil into the crankcase. In one cylinder through the intake or exhaust manifold into the other cylinder. I’ve seen it multiple times. This is a slow leak over weeks, months and years of sitting depending on the seal. The rotary gear and bearings are in a constant bath of oil so no risk of those drying out or rusting.
Premix has nothing to do with it.

Hydro locking is the big problem.
 
Joined
Mar 9, 2009
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374
Location
Ontario, Canada
#7
I guess I do, my only experience is with my 96 XP 800 I tore down for a blown motor before the injector pump with the same 3/8 hose going to the rotary valve blew the top too, which is also the same injector on the 720 I just tuned last fall....looks just like this one. I always figured the injector pushed the oil through the entire system and the return line was the low pressure side going out the bottom of the block but I'm not a SD guy, that's why I'm on this forum instead :D

You are correct sir, I just did a check on how those lines run, I was partially right but you have it. The attached pic shows that indeed the 3/8 line goes both to the injector and to the cases. Either way, carry on and hope it all works out for the OP with the project.
 

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