waterfun

Just purchased 1994 polaris sl 750...great shape...we are new to the world of PWC...so far so good...only issue with the ski is after about 60 minutes of riding, we loose spark to one of the cylinders....loss of power and no rev over 4000...new plugs and caps...gas is good and filters clean...when it runs it runs great ...48 to 52 mph with lots of power...what's happening???..any thoughts would greatly be apreciated...

PS: Really enjoying this site....Thanks to all for supporting the cause...please keep up the interest.

GCwaverunner

Ok. So its defintely spark????? Did you check it under load??? Have you checked compression?? Have you replaced high tension leads??? If it has no spark to that cylinder it can only be the plug, lead or coil. Otherwise it will be a carby problem! If it had weak spark under load it would be on all cylinders so im thinking it would be carbs. Im not familiar with that motor however the general set up I think is similar to the Yamaha 700. Does it have 2 carbs or 1? let me Know.

waterfun

Motor is a Fuji blue 3 cyl, 3 carbs 750...
I have pulled the cap off the cylinder in question while motor is running and no change...replaced plug (black and wet) and still no fire...we pull the ski out of water leave it sit and then its back to normal...
We have not done a compression test...unit starts well and runs great...the ski itself had been sitting stored indoors for about a year...
we have replaced plugs, caps and cut back the wire ends...is there anything in the black box we can check??...you mentioned coils...would it cut out after it gets hot??..its all new to me..


Thanks so much for the response...