My engines will can make 2 different sounds...which is best?

[blue_collar2]

A little hard to put this in words...

I've noticed that my (2-cycle) engines can make 2 different sounds when running, and sometimes they will change from one to another in flight.

I had thought that one sound is "right", meaning a good mix...and the other was "4-cycling" which means the engine is too rich. I guess I don't understand completely.

Can anyone shed some light?

[RC-Bearings]

When the engine is in the right range, it sounds smooth. When four-cycling, it sounds lower pitch and rough. If it is changing in flight, it is too rich. Lean the main needle a click or two at a time until the four-cycling goes away. This is a safe setting but may not be generating the best power.