My Sportsman 500 runs good but won't idle. Then it started to run crappy, coughing, like the choke was on. My local dealer found the carb diamphram torn, replaced it but it still won't idle. I read somewhere that the cable adjustment if off would prevent it from idling.

Anyone have any ideas?

thanks

 

find the idle screw and adjust the idle. set it so that it is just high enough so that the atv will not turn off when your stopped and in gear. before adjusting have the engine warmed at normal operating temperature.

 

Turning the Idle screw doesn't seem to affect it, one way or the other.

 

your carburetor has an obstruction in one of the many passages it has which is not allowing there to be a difference in rpm when adjusting the idle screw. it needs to be taken out and taken apart to be cleaned and/or rebuilt.

 

My mechanic did that but is going thru the carb again to try to find the obstruction. When it first happened, I figured it was a clogged pilot jet. There has to be something inside clogging but we haven't found it yet. I was posting to see if there was another factor we weren't aware of.

thanks for the tips, most appreciated

 

If the problem is just idling you might want to check the throttle cable that comes out of the throttle housing. If it idles when you give it a little bit of throttle and it shuts off when you let the throttle go, this is probably the problem. There are two electrical contacts in the throttle housing, which, if they make contact, will shut the engine off like a kill switch. You need to adjust the cable free play on the throttle cable. It is the cable that comes out of the throttle housing. About a foot or less down there is an adjustment under a couple of rubber covers. Slide these off and tighten the free play until the two contacts in the throttle housing have about 1/16" of gap between them. (You have to take the throttle cover off to check). Let us know how this works.