I have a 2005 Sportsman 500 H.O. 4x4. I purchased it used this summer and used it a few times. I fired it up now that it is cold to plow some snow and have encountered an issue. After about 4 or 5 minutes of use, the throttle revs up and continues to get higher and higher. I can't shift it is so high, and it is barely held back by the brakes. I have to shut it off, pull it in the garage and wait until the next day to start it. I get the same results.

The throttle cable is not seized as I can still give it more gas but it acts like it is stuck or getting choked. It didn't do it during the summer but does it now. I don't know if it coincidence that it is cold or if it is part of the problem.

Any thoughts or ideas would be greatly appreciated.

Thanks.

Since this is a carb'd model I would make sure you run fuel system de-icer in it as it is acting like our sleds do when they come from warm to cold especially if not using fresh fuel. I would add isoproponal or fuel injector cleaner which also contains iso as well. Make sure the throttle cable is lubricated as well and not sticking but I would put money on your carb's icing up. If you do not sure the problem you will be having engine problems as the engine is going in to a lean condition and that is why the higher revs. An easy way to check for fuel issues is to pull the choke when this occurs and if the speed decreases and idle returns to normal you know that you may have ice. I would alos feather the choke just before you shut it down for the day as this will bring fuel into the choke assembly and take out any moisture as well and assist in easy starting the next time.

Good Luck from Canada

I agree check your choke and throttle cable. Possible you have an obstruction in your carb, that it not allowing your throtle cable to work correctly. It's a bear to get the carb off, but take your time and it'll be worth it.