I ran 56 gallons of fuel through the FT 120 gemini II before the right jug blew off of the crankcase due to metal fatigue.
The carb on mine was the old design airbleed for the idle mixture. The idle mixture was set just slightly rich which worked fine at 458 ft. ASL. Never had a flameout or a dropped cylinder in the 100 plus hrs of run time.

I also ran 2 of the 160 twins which make enough power for a pretty good sport motor. One had the old airbleed carb while the other had the newer twin needle unit. I ran 10 and 15% Omega fuel in them summer and winter and could tell little difference in the carb performance between the two.

The 120 Gemini II and the FT160 are good reliable smooth not too powerfull engines that require very little maintenence or needle valve adjustment once they are set up. Adjust and lube the valve train a couple of times per year and change the plugs out about every 10 gallons of fuel whether they need it or not and turn the needle valve in or out about 5 or 6 clicks summer to winter and you are good to go at these altitudes.


I still have a new in box 120 Gemini II that has been here for years since I slid over into gas back in the 90s.