My redmax eb431 I think thats the model. Anyway when its below 60 degrees out the blower starts but you cant hit the throttle for atleast 2-3 minutes. I literally have to start it and walk away. If you do hit the throttle even slowly or just a little tap it makes this sound like the engine has a miss fire. In some cases it will pop and give off what sounds like a backfire.The blower will shake noticibly almost violantly! IT has done this since day one when it was brand new...when it had a fresh fuel filter, fresh fuel, fresh plug...fresh everything!