RE: HELP! Prop for O.S. 1.60FX
I think a Zinger 18X6-10 would be a good place to start. A Menz or Zinger 20X6 is another suggestion. Use any prop that keeps the engine RPM in the 6500 to 7500 range and you should be okay...
I am basing this on research I did for my ST-3000 and I think it will apply to the O.S. too...