I just bought my son a 2008 Polaris sportsman 500. He loves it, but when we start it, it idles perfectly at 1170 but when we touch the throttle, the idle skyrockets to about 2400 and will not come down. It does this when riding and we can't shift to reverse etc. If we shut the key off and restart it, it is at 1170. We searched the forum and tried using seafoam in the tank as we read it could be clogged injectors, but it didn't help, as I guessed, since it works fine after shutting off. Any help would be appreciated.

 

sounds to me as it is a throttle cable sticking

 

If it was the throttle cable, it wouldn't correct when you restart would it? If we shut it off when it's running high, and restart, it idles perfectly every time.

 

the throttle cables are touchy I have noticed on my 2011 if I play with or move it while running the idle changes drastically until I get it to the right spot again if its starting and idling good until you move the thumb throttle then wont settle down sounds like its sticking you turn it off and start it again and its fine so either its sticking, not in the correct position, out of adjustment. just my 2 cents is all

 

you should be able to adjust the cable play or at least check it. while it's idled high(check w/ brakes on),try moving the cable around some and if it changes the rev's then it most likely the cable. if not, then it might be an major air leak where it will not idle back down(like a cracked carb boot)or some other restricten of fuel and more air then needed. just an idea.

 

Fixed it!! Thanks Stendori for the winning answer!! Also thanks irinman for your input. We did find an air leak on the flange that bolts to the motor. Tightened it and it runs incredible!! Love the ATV connection!!

 

wow, i got one right lol your welcome and glad the forum is helping.

 

ehhh, ya throw enough rocks and sooner or later one makes it into the pond, Stendori.....lol