Ideal RPM (s)

[Rivets]

Bert said your edger would be the SAME as a mower. The numbers he posted are the ones I would use, as he also said, NO MAGIC NUMBERS. Very uncommon to find RPM specs for the older engines.

 

[sgkent]

Thanks. So a 21" mower blade is 21" x 3.1416 = 65.97" \ 12" = 5.50 feet per revolution. I have read that the suggested current tip blade speed is 215 mph which is 18,920 feet per minute. 18,920 feet per minute \ 5.50 feet per revolution = 3440 revolutions per minute unloaded at high speed. That is really close to the 3600 max RPM so it would be hard on engine life, However Toro customer service specified for my 21" mower (Honda / Toro) to set the engine RPM to 3000. I guess I will set everything to 3000 unloaded and the tiller to 2700 RPM fast / 1750 slow. Thanks everyone. That pretty much agrees with what everyone has said also.