Custom/Hybrid Update: HELP - cooling problem

[96superjet]

Yes... I had taken everything apart including hooking up the garden hose to the head pipe. Water did come out, but on continued further inspection there was a rock stuck in the bottom 90 degree fitting. Lesson learned.
Step one remove all brass fittings and visually inspect. Apparently garden hose water can still get by and fool you into thinking all is well.

Ski has been running great all summer and the other day the pisser that comes from the barb on top of B-pipe stops throwing water overboard.

So I started with the usual diagnosis process. Disconnected dual cooling at pump and checked both brass 90s, hooked hose up to rear cooling lines and blew water up into hull (I have quick disconnects installed just inside the hull for easy engine removal), pulled the B-pipe and hooked it up to hose, the chamber filled up with water and it shot out the top barb as it should and also came out the bottom screw hole which I have open 3/4 of a turn, I pulled the head and there was some gravel around the rear cylinder (flipped the ski upside down blew it out with compressed air).

After all of this it's still not pushing water out of the top pisser. Took it down to the water to test and after about 5 minutes the coupler between the pipe chamber and water box was frying and steam came off the waterbox when I splashed water on it.

Has anybody seen this happen before and does anybody have ideas or suggestions.

Sorry for the dark video, but it was late.

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[Kny21]

Have you tried back flushing the ski? That's the best to remove objects and build up. Else start pulling all the hoses and blow out with air. Could be something at the pissers or if you have restrictors.

 

[tomski]

Your piston is clean.

 

[96superjet]

Your piston is clean.

and that's 3 seasons on that JM781 motor. Hooray for Pennzoil full synthetic and Citgo 91 octane pure gas (no ethanol).


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[tomski]

Try again, the piston should not be steam cleaned.

 

[96superjet]

Try again, the piston should not be steam cleaned.

I don't follow. That picture was taken minutes after removing the head. How would it have been steam cleaned?


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[jetfreak78]

The piston has been steam cleaned by the cooling water through a faulty head o-ring. This Explains the loss of presure in the cooling system. Check/Replace head o-rings

 

[DAG]

Yup defiantly want to look into the piston, water is getting to it. Hopefully its just a o-ring but it could also be domes beat into the head shell. You can check for a step in the mating surfaces to indicate it being worn. It could also be a warped head or warped cylinder. Just a few things to check when you have the head off. But that's only a very little bit of water getting in so it does not account for the pressure loss for a pisser not pissing. My bet is it's a effect of the cooling circuit being cloged and got the cylinder warm enough to damage the o-rings

I like the back flushing idea. It should be a easy to locate a clogged line or do you think the clog is within the cylinder or exhaust manifold

 

[smoofers]

In addition to the piston being clean, I'd also check all of your cooling lines for obstructions. In your picture the water jackets of your cylinder are filled with gravel!

 

[Blue]

Good catch Smoofers. Ur right that is gravel. You will definitely need to check the entire system for obstructions. Small pebbles can easily get stuck in any elbow fitting blocking the water. I bet the water obstruction cooked the orings.

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