What size prop should one of these spin. I fired one of the engines up yesterday with a Master airscrew classic 20x8 with 1 inch cut off each tip, It tached at 5200. Temp was 89.6F humidty was 36%. Fuel was normal unleaded with coolpower syn oil at 50:1. I see on a thread elsewhere that the engine size should be on the cylinder behinde the muffler,but nothing there.
Cheers.