How do you know what the best RPM/Tach reading is for your engine regardless of prop???
Do you basically still have to go by ear with the engine screaming leaned out to the max and then back it off? Or is there a base line standardized tach reading for each engine?
Or do you go with the Practical rpm range: 2000-20,000 lean it out until you hit 20,000 RPM?

I just about burned up my OS 50 SX By running it lean trying to get as much power out of it... at the time I did not have a tach to see what it was turning.
I think some have been turning 12X4 props at around 17,000 RPM? How do you know when the 17,000 is as high as you can go without burning the engine up?