98 Gts Loss Of Power Top End

[tnjetski]

Hello everyone, I purchased a 1998 seadoo GTS last year and it ran perfectly all season the only flaw it had was it would only run with the fuel selector on reserve, would get no gas in the on position. At the end of the season I added some stabil for the last run and stored it for the winter (about 7 months ) got it out of storage last week topped it off with fresh gas, put two new plugs in, and to my surprise it started on the first try. on the first trip out it ran fine for about one and a half hours but then started losing power at full throttle in a very rythmatic pattern about one second of power then about one second of power loss but not like it was out of gas motor never stalls and then picks back up just a constant up and down surge of power, ski runs fine at half throttle, never hard to start, idles perfectly, thought I may have fouled a plug, the next day I put 2 more new plugs in , ski ran great for 5 minutes then started the same power surge at anything over half throttle, put it away for that day,the next day just for troubleshooting purposes took it back with same plugs and doing nothing to the ski and again about 5 minutes of running fine then the same problem started again. I would appreciate any advice I could get on this subject.
Thanks in advance John

 

[seadoosnipe]

Welcome John!

Welcome to the forum John. Your GTS has the 717 engine in it (one of my online sources showed it being the 4-TEC!....I almost died. Had to be a mistake) and you may need to answer a couple questions.

What are the rpm's when this happens at full throttle? Have you done any carb work on it lately?

From your description, sounds like your hitting your speed limiting governor. The way it works is whent the rpm of the motor starts crossing the line (7200 rpm, if I remember right) then the mpem will limit that by cutting power to the coil. So, check your rpm. If your hitting the governor, then makes me wonder how lean your running? You haven't adjusted the speed/mixture screws?..........re-post.

 

[tnjetski]

98 Seadoo Gts Losing Power On Top End

Seadoosnipe, thanks for the super quick response to answer the questions you asked NO I have done no carb work or adjusted the speed mixture screws don't even know where they are. But just from memory of last year it does seem to smoke a little bit less than it did from last season, As far as the RPM's , I have no idea what rpm I am reaching because this jetski has all of 1 gauge (fuel gauge with a idiot light for low oil) I have checked the compression it is about 150 psi cold and about 140 psi warm. I was just wondering about your shock of the 717 4-TEC engiRIDEne I have no idea if that is actually what it is but is it a notoriuos dud.
Thanks again for all your help
THIRTEEN YEAR OLD SON READY TO RIDE