02 Seadoo GTI LE water leaking into cylinders

[bdesim2]

Hey everyone,

I just rebuild my seadoo GTI that has the 717 motor. After the rebuild I noticed it was running really bad when there was water introduced to the system. I pulled the head and clearly can see water getting in while running. The gaskets are new, Head was torqued properly, and have checked to make sure cooling system is clear.

Only thing I can think of is I accidentally reversed the Cooling system in and out. Can someone verify or maybe suggest where to look next?

In the picture the input to the head goes to the top of the jet pump.

Out goes to the left side.

Thanks for the help.

 

[mikidymac]

So the water coming from the garden hose fitting goes to the arrow out on the head. THe hose from the actual pump goes to the arrow in on the head.

However, this will not cause water to get into the cylinders. You either have a compromised gasket surface, bad o-rings or uneven cylinders.

 

[bdesim2]

That’s what I was thinking as well. I’m going to have to check the surfaces and the gaskets look perfect.

 

[mikidymac]

The thin black o-rings that seal the combustion chambers should get some 518 sealant per the manual.

 

[bdesim2]

I used some three bond initially. I’m going to check the mating surfaces to make sure they are level. Hopefully everything is going to turn out ok. Machine was not overheated so I can’t think of why the head would be warped or not straight.

 

[bdesim2]

Hey,

I resealed and torqued the top end on my GTI. Still leaks. It’s leaking in both cylinders. I’m wondering if it could be coming in from the exhaust? The mating surfaces look perfect and everything seems to line up. No cracks anywhere that I can see.

Could it be leaking from the exhaust gasket on the manifold?

 

[mikidymac]

So seadoo uses two separate cylinders unlike most manufacturers. You have to install the exhaust manifold hand tight when installing the cylinders to make sure they are even and together, it’s also good to push the cylinders together tightly so the two are almost touching. Then torque them down per spec in a cross cross fashion per the manual.
Finally when the head goes on you need to try to center it on the cylinders as best as possible.

Why seadoo didn’t use alignment pins and dowels like the Japanese we’ll never know.

 

[bdesim2]

So seadoo uses two separate cylinders unlike most manufacturers. You have to install the exhaust manifold hand tight when installing the cylinders to make sure they are even and together, it’s also good to push the cylinders together tightly so the two are almost touching. Then torque them down per spec in a cross cross fashion per the manual.
Finally when the head goes on you need to try to center it on the cylinders as best as possible.

Why seadoo didn’t use alignment pins and dowels like the Japanese we’ll never know.

I used this method when installing the cylinders. I’m going to pull it off and try it again. I used a little bit of threebond on the base gaskets when installing. Is that normal on the seadoo? I do this on Polaris motors with no issue but figured i would ask.

 

[mikidymac]

The 1211 on the base gasket shouldn’t change anything.

 

[bdesim2]

Thanks. I’ll check a few things and see how it goes. Hopefully this fixes it.

 

[bdesim2]

Finally got around to checking things out. It seems that the head rocks a bit on the cylinders. It’s almost like the center is higher. I loosened and tightened the cylinder bolts. Retorqued everything and it was not any better. How do I check which part is not straight? Cylinders? Head? If it’s the cylinders can a machine shop fix that for me? I just had them bored and new pistons to match.

 

[mikidymac]

I honestly have never run into this. Are you sure the cylinders are cases were perfectly clean?
You could always take the head to a machine shop to see if it is flat.

You shouldn’t have to have anything machined though, something isn’t right.

 

[bdesim2]

I honestly have never run into this. Are you sure the cylinders are cases were perfectly clean?
You could always take the head to a machine shop to see if it is flat.

You shouldn’t have to have anything machined though, something isn’t right.

I used scotch brite to clean up the cases, cylinders, and head. I triple checked it. Head is definitely rocking in the middle. The comp test hits 150 no issue but it won’t hold it. That tells me it’s not sealing properly. I’m debating pulling the motor and going over it all again (4th time) with a fine tooth comb. I’m at a loss. I really don’t want to take it to a machine shop.

 

[bdesim2]

Update:
Took apart and re-assembled the entire top end. Cleaned all surfaces and installed new gaskets. Torqued and lined up properly.

Cylinders are now holding 150 psi compression. Water test tomorrow.... hopefully that does it.