I recently purchased a Polaris 2006 sportsman 500 quad in Phoenix, it runs and starts fine in Phoenix at about 1000 ft elevation ,when I took it in my last camping trip to 7000 ft elevation I was not able to start it in morning with 50 F temp. It eventually started around noon time with ambient temp of 70F. When it got warmed up had no problem to restart . Last week I re-jetted it to size 147 down from 155 but still had hard time to start it at high elevation with cold mornings . Need to say it is not idealing very well and fluctuate. Polaris mechanic says it needs a new carburetor costing around $400 plus labor , any idea what is off on it ?
Thanks ,Kazazz

 

Welcome! Could be since you just bought it the carb might also need a new carb kit or at least replace the needle and seat(can cause excess fuel if worn) Plus 155 main jet is stock as you say, 147 may not be low enough when you take into consideration the altitude and cold also?No need of em down here in Texas,but I'm sure there are oil tank heaters along with keeping the battery on a battery tender might help,but BEST thing to do is talk to a dealer local to the area as to jetting,plus others on the forum that ride/live up there may tell you what they do. OPT

 

Thanks very much OPT, all of your recommendations make sense. what has puzzled me is why when the engine is cold and in high altitude it has hard time to start but at low elevation it starts with the first crank . I was thinking may be it has a bad diaphragm also since it is not idealing properly and in addition to needle and seat change that too.
Kazazz

 

One other quick test is to pop the air box lid and see if it idles /cranks easier at high altitudes/cold temps. Could just be the thin cold air. This usually indicates the need to drop the pilot and main jet a little further down,plus raising the carb slide needle clip which drops the needle and helps to lean the idle to mid range fuel air mixture could help also. Like I said best to talk to a good shop in the area you ride as to jetting requirements. Plus checking into the carb since you just got it isn't a bad idea either for worn needle and seat,float adjustment,etc. OPT

 

This weekend talked to a couple of dealers in town about this issue, both agreed I do not need a new carburetor but most likely the pilot jet also needed to be down sized . That is my next step to see if it does help.
Thanks again, kazazz