I was helping a friend of mine work on an 2001 800 mxz. The sled idles terrible on just 1 cylinder, but when you crack the throttle and get the RPM'S up , she runs fine!! It goes Ok down the trail. *Its's dropping the mag side cylinder. We had the flat slide carbs off twice, they were clean before we started, but we had them a part and *cleaned them anyway ( we did this twice) , suspecting that the pilot jet was messed up, it looks fine. It has spark. Were suspecting there may be an idle circuit in the black box, that's gone, and the sled will need to go to the dealer to be checked with Ski Doo's tester, we were also *wondering if a weak coil could cause this, we didn't have another one to switch out with to test this? Have any of you experienced a similar problem with your 800's? Luckily there is no snow this weekend (never thought I'd say that&#33http://www.snowmobileworld.com/forums/iB_html/non-cgi/emoticons/wink.gif so we have a few days to get it fixed....Any thoughts?? thanks DooZ

Yeah, I've had that problem. Several times. Fouled plugs. I also had the problem when one of my floats stuck open. Is the plug wet or dry when this happens?

Are the carbs syncronized?

My Summit 800 has a similar problem, but it fouls the mag plug so I have to change it. It seems to get worst when I play in the powder. It is now at the dealers getting looked at I will let the group know if anything comes out of the visit.