seadoo speedsterSK motor surgging over 4500 rpm

[Paul Herder]

one of the motors will not rev to 6000 rpm, gets to 4500 rpm and starts surging up and down. this happens when in the water, on the trailer it will go to
6000 rpm and stay there but not under load, replace fuel pump,fuel filter,cleaned carburator filter. is there like a two stage carburetor. I'm out of ideas.
This a Rotax 717

 

[Charles603]

I had a similar issue on my gtx this past weekend. Charged the battery and replaced rectifier and it was fixed for a day. Charged the battery again and it was going strong for another day. In thinking it's my stator/magneto. Might be yours as well?

 

[mikidymac]

If it’s electrical it’s typically the voltage regulator not the stator.

Sounds fuel related, I would rebuild the carbs with genuine mikuni kits and needles and seats. Do not buy SBT, WSM, Wonderosa or any aftermarket ones ever.