I have a 1998 600 efi bateryless powder special. My problems all started about a month ago when the sending unit wire fell off the thermostat, it made it foul plugs like crazy. Once I put the wire back on it still ran rich and would foul the plugs in about 150 miles and it would miss at high rpm intermintently. I read on a fourm to unhook the kill switch plug under the handle bars, after doing this it ran awsome plugs looked perfect, until the end of the day it just died so I rehooked up the kill swich conector and it fired up and ran great until the next time I shut it off and it would not start so we rechecked all the conections and everything was ok so I was setting there comparing to another ps 600 but it was carberated and it had a small screw on the throtle which pushed into a rubber thing under the throttle so we pushed mine in with a screw driver and it fired up. So we turned it off and tried to start it the same way again and nothing so we sat around for 10 minutes and tried again using the same technique and it fired up and drove it back just fine. The next day I went out and 1 pull it fired up by holding in the ruber thing and then after running for 2 minutes it died and have not been able to get any spark since. Any help would be great since there is lots of snow still in Idaho.