• This site contains eBay affiliate links for which Sea-Doo Forum may be compensated.

1990 Seadoo SI 5803 looks like it's leaking from base gasket

jaggles

New Member
Fixing up this old jet ski, replaced oil & fuel filters, new spark plugs, cleaned it up. Started it with a hose (started, turned on hose, turned off hose, stopped engine).

While it was running, I noticed water leaking pretty badly from what looks to be the base gasket. I made a video and posted it to youtube here:

Apologies in advance if this is obvious, but I am severely lacking on knowledge in this area, and I've been researching for hours. I've skilled up on how 2 strokes work, and from what I can tell, it does not sound like water is SUPPOSED to be in there. I'm guessing it could get in there if you leave it connected to a hose without the engine running (which I was careful not to do).

I also took the plugs out and turned it over a couple of times, fully expecting water to come shooting out, but.. nothing. Just air.

I smelled it to see if it was gas, does not smell like gas.

There was limited info I could find about this maybe being a "water jacket"? E.g. does a jet ski have a completely separate compartment that is SUPPOSED to have water for cooling, and that's what is leaking?

I'm stumped! Hoping someone here might be able to help me to figure this one out?
 
Sorry, it looks like I posted duplicates of this thread by mistake. I've updated the titles of the duplicate posts to have them be deleted.
 
Yes, water surrounds the piston jug to cool the engine, like a car intake of sorts. If you don't already have it, download the parts manual for your ski and see what gasket or sealant it takes.
 
Thanks! I've found and downloaded the manual, it's very helpful. However, it doesn't call out specifically where the water *should* be.

Just to confirm my understanding of what you said, it sounds like there *should* be water where it's leaking from in the video, but of course, it shouldn't be leaking.

I'm guessing I'd need to take apart the top end as it outlines in the manual, to be able to replace that gasket, correct? I.e. that's the only way to stop this leak?
 
Yes, take the cylinders off, have a look at the base gasket first, count the holes in it and order the same gasket, also order new exhaust manifold to block gasket, oring for around cylinder cover and piston o rings. Make sure you bolt the exhaust manifold on before torquing down the cylinders
 
Yes, take the cylinders off, have a look at the base gasket first, count the holes in it and order the same gasket, also order new exhaust manifold to block gasket, oring for around cylinder cover and piston o rings. Make sure you bolt the exhaust manifold on before torquing down the cylinders
 
Back
Top