SJ spitter has air....head gasket??? help!

[tipafew]

I recently had a friend blow his square nose up. I rebuilt it for him. I took it for a test ride and when I get on it hard I get some air out of the spitter. I built a number of motors back when I was racing and never had any issues.
I assumed it was a head gasket leak, so I pulled the head, lappped it and put a new oem gasket on.......same thing still happens.
I put my compression tester on it and I have 177 on front cylinder and 175 on the rear. I would think if I had a head gasket problem it would show up more than that.??????
I also lapped the exh. manifold and everything there looked good.
Any other ideas????
Boat is stock except for milled head and B pipe.

Chad

 

[Mike W]

Check the head for cracks

 

[Frosty]

did you check to make sure the cooling line was not clogged before it gets to the motor? I had one clog up with sand/seaweed... made nothing but air comeout of the bypass.

 

[tipafew]

You do bring up a good point. I really should check the obvious before I yank the motor back out. I will blow the lines out tonight and be sure they are clear.
The water stream out of the pisser has a lot of pressure, but the stream is not as full as my skiis always have been.

 

[Mouthfulloflake]

check the lines all the way back to the pump as well, a clog or debris hung back there could make it do odd things too.

Ive always noticed a stronger pisser stream with a new impeller install.
so I guess the impeller-housing clearance has something to do with it as well.

 

[Shrivel]

Ive always noticed a stronger pisser stream with a new impeller install.
so I guess the impeller-housing clearance has something to do with it as well.

Yep, after greasing up my midshaft bearing this weekend due to some cavitation, my pisser was twice as strong as it had been prior to that. I thought I must have just blown out a clog or something, but now that you mention how changing the impeller affects it, it would make sense that it's impacted by the entire pump system.

 

[crashski]

I had the same issue this last winter and it turned out to be a blown oring on my ADA head. A blown head gasket well do have the same reslut as my oring. I ran a compression test and found my front cylinder was off by 10 psi. Went and replaced the oring the compression came back up and matched the rear cylinder and had a steady stream of water after that.

 

[tipafew]

Well, I definitely think it's a head gasket. Last night I hooked my flush kit up to the manifold and ran water through the motor only(bypassed head pipe). Water stream was nice and steady. The second I fired the ski I got a big ole burst of water and when I revved it, I got a lot of air. I am wondering if it could be the cylinder. We lapped the head and put a new gasket on already.
I will pull the head tonight.

 

[keefer]

It could be the exh manifold gasket leaking into the water jackets. I would check the cyl deck and head for flatness first.

 

[chrisdoc0608]

welcome to what i have been going through for the past two weeks! let me know what you do if you fix it, bc im to the point where im going to go and get my head remilled just to make sure it is flat.

 

[tipafew]

Well, I pulled the head again and it was definitely the head gasket. You can see where is was leaking.
I took a flat bar to the cylinder and the sleeve is setting low where the leak is occuring. The other side of that sleeve looks okay and the other cylinder looks fine. It doesn't show any evidence that the sleeve has moved from anything I can see. Hmmm. Now the question is...How much can be shaved off before I run into issues??