My manual for the subject states the initial setting for the mixture valve (low speed needle valve) is 3/4 turn open. Is this correct or is it a typo? I have three OS46FX and they all state 1-1/2 turn open in the manual for the same valve. I am trying to understand why I am having so much difficulty adjusting this engine. Right now I would be happy if you could just answer my first question. I have the valve open closer to two turn. The engine is still not correct.

A friend who was helping me told me that he and 4 others, very experienced with R/C engines, had given up on his new OS46AX because they could not tune it. I realize that does not give you anything to work with. It was not encouraging to me. Have been flying R/C since 1972. Any problems with these engines?

When it says 3/4 of a turn, it doesn't mean for regular flying, it is just to breaking the engine in with the glow drive on for a little while at least. You start with it like this to keep it very rich too much infact to run the engine without the glow drive on, but you quickly lean it out to, like you said, ~1.5 turns. Hope I helped some, good luck.[sm=wink_smile.gif]

The idle mixture can be almost anywhere to start with, but a rich setting is desired. Please be aware that it's the high-speed mixture that you set at about 2 turns out from closed for initial running. You lean from there. Run the engine at full throttle.