1996 Seadoo XP won't turn over with PTO plug in

[Oleg Russia]

I will write again that in case of a problem with the cylinder, you would not have a starter spinning, but in the video you have it spinning. if the starter is spinning, then the bendix is spinning. and if the bendix is ​​spinning, it means that it does not catch the flywheel with its teeth. I hear that it is not blocking and does not make the wrong noise. if the cylinder was locked, you would only have a click of the bendix on the flywheel and no more movements and sounds.record a normal video for a few minutes so that you can see and hear everything. I also don’t understand. Can you turn the engine by hand when this problem occurs?

[AL_Mark]

I agree with Oleg. When you first mentioned you got 150psi out of a 96 SP - that is pretty high for this old ski unless someone modified it. (pistons or head). Why the bendix would engage when compression tester removed and when installed is not logical, unless when the piston gets to the top of it stroke and hits the insert, the position of bendix and fly wheel notch is not quite lined up.

Compression Testers in my view normally read low in use, since I have tested them on a calibration standard with and without the schraeder valve in them. They read higher when the schraeder valve is out. I believe the schraeder valve limits the flow and its spring causes a differential between the before and after the valve. But you need the valve in it or you will never get a reading. I know my harbor freight compression tester reads about 30 psi lower with the schraeder in it than without. I got a better one from autozone that does not show this large of difference, and modified the harbor freight for leak down testing.

Mark

[ghebert1111]

Let me see if I can get that starter back on and get my son to video the whole process and post it up.

[ghebert1111]

OK, please see videos below

Watch "hand turning with starter NOT installed" on YouTube


Hand turning with starter installed


Starter testing


Starter in ski, directly connected to battery

[ghebert1111]

Working on more videos. But I did hear a thunk that shouldn't be there. Didnt get it recorded but will try.

[Oleg Russia]

Working on more videos. But I did hear a thunk that shouldn't be there. Didnt get it recorded but will try.

what was the point of shooting visible with the head removed? you still haven’t answered when the engine does not turn with the starter with the spark plug installed, can you turn it by hand?

[ghebert1111]

what was the point of shooting visible with the head removed? you still haven’t answered when the engine does not turn with the starter with the spark plug installed, can you turn it by hand?

Not sure what my point was. When I'm trying to fix the TV I like to make sure it's plugged in first, so I guess I wanted to confirm that the pistons are going up and down in the cylinders.

[ghebert1111]

More videos.

First attempt at starting with head back on and no plugs in


second attempt at starting with head back on and no plugs in


Starting with rear plug in part way



Last one

[Myself]

Working on more videos. But I did hear a thunk that shouldn't be there. Didnt get it recorded but will try.

Yes, there is a slapping noise that doesn't sound right. Rotate the engine to bring a piston to TDC. Rest your fingers on the piston top and rock the PTO back and forth. A loose lower rod bearing can be 'felt' this way. That's kind of what it sounds like.

[AL_Mark]

I don't know much about the sea doo motor breakdown of that vintage yet. Yamaha man here. Is does sound like a knock. Anybody know the thickness of the head gasket should be or what the piston clearance is suppose to be when you use something like a wire of solder?? The plug was not in there to deep and looks like the length used in a Yamaha. Is the correct plug being used? Did the piston have marks in it when you had it off? The crank connecting rod journals should not be the problem if they slipped on the main journal should they? In relationship to the center of the crank that should not make the piston to have a longer stroke. Most cranks are not made of one cast or solid. Just throwing these out there to everyone.

Maybe time to break it down and look at the crank, connecting rods, wrist pins and all bearings. The cylinder wall condition did not look that bad for what I can see. Your going to have at least $200 in it for parts to just take it apart and put it together - not including anything broke or damaged.

Mark