Re: rpm falls to 3000
You don't have a waterpump, the jet impeller forces the water through. You should have a water filter, probably at the bottom of the engine compartment. Clean that out completely. It has an o-ring that you may have to replace. They usually have them in well stocked hardware stores that will fit if you take the unit with you.
You may have something stuck in the thermostat, but save that for last, because you have to pull the engine to work on it.
Water passages have two water deflectors on each bank of cylinders that can go bad and overheat one side or the other. Again, you need to pull the engine to work on those. The parts catalog for your setup are on-line at the BRP site:
One other thought is that the ignition coils need to be kept well grounded and they tend to corrode and lose contact where they are bolted to the cylinder heads.
http://epc.brp.com/default.aspx?brands=ej&lang=e
When you get to the first picklist, scroll to Turbojet.
You need the very best oil for that rig. I would run it on XD100 if it were mine. Don't use plugs any hotter that a QL77JC4.
