96 GSX 787 Rotax troubleshooting help

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I have a 1996 GSX with the 787 Rotax and am in need of some troubleshooting help. Bought it a year ago from a guy who barely rode it and as it sits now it's only got 50 hours on it.

A few weeks ago I cleaned her up, put all new fuel in it, Ultra 93 non ethanol and took it out for a rip. Started up in the water and required a little warm up at idle. A little coughing as I had expected after not being run for a while.

Got up on the throttle and it bogged down basically back to idle for maybe a min then started to clean up but teen then it was running like dirt up until around 3000-4000 rpm then just passed 4000 rpm it basically takes off and runs very smooth. Ran pretty good for about a half hour. Riding pretty hard almost full throttle the whole time, now this is where the bugs start coming up.

While cursing at around 3/4 power the thing just up and quits. No bogging down or anything, just goes dead in the water. Take the lanyard out then put it back I and fires up no problem but then 15 min later the same thing happens. Go to restart it and I can smell exhaust and gassy smell assuming it's probably flooded.

Get it started with choke and limped back to the dock just above idle, whenever I would try to get on the gas to speed up it wouldn't take and just started bogging at any use of throttle and get really smokey from the exhaust and stink of gas/oil.

Got new plugs in it because the originals looked pretty bad and had improper gap so got new. NGK to spec. Cleaned fuel filter, Took it out again and the same problem persists. Check plugs and they're fouled. Plug the hose into it and run it on the trailer and it runs fine but that's out of the water. Pugs are gummed up with oil and fuel again and the exhaust is very smokey when I give it the throttle.

I've thought about taking the carb off and cleaning or rebuilding, or putting fresh injection oil in but was wondering what anyone else had to say and maybe can shed some light onto the topic before I start any wild goose chases.

Thanks all.
Does it still have the old grey tempo fuel lines? If yes, those need to be replaced ASAP. Your carbs will need cleaned or rebuilt, and you should clean or replace the fuel selector.
I replaced the fuel lines and cleaned the fuel selector valve, I recently rebuilt both carbs fully tore them down and rebuilt them with new needle and seats and pop off tested resulting in good pop at 37 psi and holding pressure. I also rebuilt he RAVE valves. While taking off the PTO side I noticed a lot of oil caked on the cylinder. Tried it out today and idles great and runs alright but it won't exceed 5000rpm. The throttle is wide open but won't pass 5000. Anything ideas gents?
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