98 XP LTD loses half its RPM at end of day

[deckspotter]

So I've got a 98 XP LTD that's giving me a fit:ack:. After about 6 hours in the water my ski suddenly won't go over 3500-4000 rpm and smokes a lot. I checked the compression and got 150 in front cylinder and 170 on back. No water in cylinders either. Thing that's really throwing me is that when I take it out of the water and drive it home (hour or two), it runs in the 7000+ rpm range. This is the third time is done it to me. I don't think it's carb as the ski runs great for the first six hours or so. Anyone have an idea?

 

[cdnbikerdude]

Well you can start with these... there is nothing special about your problem:

Rectifier
Carbs Clog
Grey Fuel Lines
Filters in Carbs

 

[col84]

Is it a stocl motor?If it is your compreesion shouldn't be that high.

 

[custompartsguy]

yeah 170 seems to high on that one, get a cold compression reading and then when it acts up get a hot compression reading.

 

[deckspotter]

So I ran a cold compression and got about 130 on both cylinders. Next time it acts up I'll check the spark. I'm thinking there might be an electrical issue with the coil. Its hard to ignore that the ski runs fine at 7000ish RPM, then suddenly will barely get 3500, all with good compression. Does that mean anything to anyone???