I have a Rancher 350. I was rideing today and when I slowed down and let off the gas it backfired scareing the **** out of me. WTF I turned the air/fuel mixture screw 1/4 of a turn like a month ago it dident backfire till today. So I just need to turn the air/fuel mixture screw another 1/4 of a turn out. I think I am loseing compreshion.

My atv has blue smoke comeing out of the pipe. Some dude told me that the fuel mixture is to rich is this true.

 

We are seeing posts like this all the time! Fuel has dried up and clogged up your slow (idle/pilot) jet. The fuel screw will only help you so much, then you are going to need a carb cleaning, paying particular attention to that jet.