95 Seadoo Speedster bad magneto

[jasonrunner]

Could a bad magneto cause an engine to not reach max rpms?

The engine that has the problem seems to rev fine while out of the water, but when its put in the water it revs much lower then it should.

The engine has a rebuilt crank, new pistons and carburetor.

I know the magneto is bad, the battery does not charge and it does not allow the tachometer to work. Could that cause my problem?

 

[parrothd]

Test the rectifier...

 

[kimnallan2]

Hi there I am having a similar problem. My boat will start and run in the water for awhile. After about 15 minutes one engine dies and will barely turn over as if the battery is dead. I leave it sit for a few days and it starts again. I changed the rectifier hoping that would solve my problem as it had no spark previously when it died and then I read to disconnect the two yellow wires on the rectifier and if it has spark I have a faulty rectifier. I just put a new battery in the boat on the side that is running good. The side that stalls is an older battery. I think I may have over charged that battery with too high of an amperage would it cause my boat to do this? Thanks for any input. This side of the engine does not have proper rpm's either yet all four cylinders have 150 psi.