High end power issues

[Brad37767]

1998 Sea Doo Challenger. starboard motor, RPM jumps up and down 700 rpm's at full speed. don't believe it is cavitation because if I replace plugs it is good for a few minutes. any suggestions would be appreciated. RAV valves maybe need to be cleaned???

 

[Mraw]

Hi, i would repost in the 2 stroke section but if it runs fine after putting new plugs you may be running rich, first I would do a compression check, it should be 135 to 150. Any less and you will need a rebuild. If compression checks out clean the rave valves, do a Google search and you will find a good tutorial, next rebuild your carbs with knly genuine mikuni rebuikd kits including new needles and seats