rejetting a snowmobile carb for elevation changes

Q I have 2011 Ski Doo MXZ 550F snowmobile for use at my cabin in Beech Mountain, N.C. This is my first sled. The sled was purchased at a BRP dealership in Ohio in May 2012. I was told that because of my elevation (4,200 feet above sea level) that I should install different carb jets and clutch spring which I had done at the local BRP dealer who does not sell snowmobiles. Since that time I have had a hard time starting the sled. It will start after I get it back from the dealer, but after running a few minutes it will die and not restart. I try to run it every month or two on a jack and use BRP stabilizer. It starts with 1/2 choke, runs for a few minutes, quits and won’t restart. I am wondering if I need a new carb because the carb and clutch spring are the only things that have been touched since I bought it. – Ted, AmSnow reader

A It is not uncommon to re-jet for elevation changes. The elevation you are riding typically should not need much of a change, if any at all. Most snowmobiles are set to handle elevation changes from sea level to around 4,000 feet. This may be the issue with the sled. It sounds as though the carburetor settings need to be adjusted accordingly. If the machine starts on choke and runs, proceeds to die and will not start, the assumption is the jetting is too lean. Jetting the snowmobile leaner would have been the common practice for higher elevation. If the choke is used, does the machine start up at the second time? Lastly, it is not uncommon to have to clean the carburetors’ on your machine yearly, as additives do not typically prevent all the possible clogging issues. – Jason Houle, Straightline Performance