1997 Polaris 4x4 400 high idle run a way. idles rough. give it just a little gas and it tries to run away, i am sure its an air leak but not sure where. i am leaning towards the exhaust pipe as i can see smoke coming from front of engine problem is how do you tighten it up as its held together with springs. any ideas.

 

my 2000 sportsman 500 did the same thing 1st the carb idle problem is the nedle and seat polaris carbs are verry prone to dirt that will cause all kinds of funny stuff.. order a carb kit from MOOSE atv an install it and it should be fine..
2nd the exhause uses a small donut gasket inside taht pipe that is held togeather by springs relace it and it will cure the leak..

 

welcome to the forum. you should change the size of the font to a smaller one. it won't be the exhaust leak to make it do what it's doing. the air leak would be sucking air in while your exhaust is pushing out. check around the intake boot or a cracked boot it self. maybe the crank seal is bad. your sure the throttle is not hanging up some where and not returning to normal form the spring pressue? just a couple of ideas.