I second that, 17 years flying and never used one. I don't even know any plane guys that do.

Follow the advice given above by Piper_chuck to tune your engine, it is all done by listening to the sound and hence RPMs.

Once you get the feel for this it is quick and accurate. Every engine will need adjusted ever so slightly each day you go flying. These little engines are effected by changes in the air temp and humidity. Also, if you change fuel brand/mix or buy new fresh fuel after running on old stuff, you will need to check mixture.

Car guys use heat guns, but they don't have big windmills on the car.

happy flying