too much compression?

[groberso]

Please, some advice.

I have a 1996 sportster with a 717 engine. A seadoo dealer put 2 new pistons in it a couple years back and it ran fine for awhile. Then it would start cutting out while going full speed, just like it was running off one cylinder. It would not die, but it would just barely get you back to the loading dock. When you went to crank it the starter would sometimes begin to lock up.

That was last year, here is the main problem now. Thinking it needed a new starter, I put a new one on. Same result. It was locking up after maybe a half turn. I removed both plugs to see if the engine was locked up. The starter wizzed. No problem. Put one plug in, the starter turned the motor again, but you could tell there was a lot more load on it. Put the other plug in, (both plugs in), starter locks up.

Am I out of time? It does this with the wires off plugs. Do I have a valve stuck causing too much compression. Sorry, but not the best with one of these motors.

need help!

 

[kustomkarl]

It does this with the spark plug wires off the spark plugs or with the spark plugs out? I would check the compression first to see what it is. Here is some information on compression test;

You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot and there is a problem.

I would check the ground cable going to the starter to see if the connection is good and it is getting a good ground. With a bad ground it will do the same thing as you describe.

I hope this helps you.

Karl

 

[robin savell lloyd]

It sounds like the seadoo dealer turned your engine into a super duper hyperformance engine. just kiding. You could be haveing multible problems. you may be having a carb lean condition along with a new bad starter. who knows? I would pull the plugs out and give it a compression test and report back. :cheers: