DUPE - please delete - 1990 Sea-Doo SI 5803 looks like it's leaking from base gasket

[jaggles]

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?

 

[Venturian1]

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?

Looks like the cylinder base gasket is leaking, Check the squish gap before disassembly so you'll know how thick the new gasket needs to be. Also, warm it up before you begin, those head bolts are stainless, but they twist off easier than expected. Aluminum expands more than the stainless steel. Actually, before you pull the motor, crack them loose 1/8 turn in the proper sequence, then do them all another 1/4 turn. If you find any stubborn ones, snug the others back down and run it without water, with a hand on the pipe, and when it starts to feel hot, shut it down and try it again

 

[Venturian1]

Looks like the cylinder base gasket is leaking, Check the squish gap before disassembly so you'll know how thick the new gasket needs to be. Also, warm it up before you begin, those head bolts are stainless, but they twist off easier than expected. Aluminum expands more than the stainless steel. Actually, before you pull the motor, crack them loose 1/8 turn in the proper sequence, then do them all another 1/4 turn. If you find any stubborn ones, snug the others back down and run it without water, with a hand on the pipe, and when it starts to feel hot, shut it down and try it again