Sportjet 90hp 1995 wet start issue

[Onekeo]

Hello Jetboaters,

I have a Sportjet 90hp 1995.
I have no problem dry starting the engine
But when I plug the hose on. The starter have hard time cranking the fly wheel and the engine doesn't fire up.

My spark plugs and starter are brand new.
I have 125 compression on the 2 top cylinders. The bottom cylinder is only 30.
I just changed the exhaust manifold gasket but their seem to have some water going to my cylinders.

Can somebody help?

 

[RedBarron55]

Water leaks from water getting into the cylinders when on the hose almost drove me crazy.
Usually if you have water in a cylinder the compression is higher than the others since water is not compress able.
You could remove the spark plugs and see if water runs out of a cylinder with the water on.
Mine did this.
I found that on my engine the gasket between the base and the engine block was incorrect and water was leaking from the water jacket around the exhaust into the exhaust log and would fill the cylinders and the starter will not turn the engine over.
With only 30 lbs compression on the bottom cylinder (the first one to get water into it) you could have already damaged that one.
I posted a series of pictures and write ups about my travails here a while ago.
Basically the proper base gasket seals the passage from the old water inlet when the block is used in an outboard from the base. The base has a depression that goes under the exhaust outlet and if that gasket has failed or is one for the outboard instead of the jet water flows right into the exhaust and from there into the cylinders.
After finding this I have filled that 3/4" hole with JB Weld to make sure it doesn't leak on my jet.

 

[RedBarron55]

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