I have one in a TRC Zero. Don't fly full throttle, but I can tell you the engine is very fuel efficient.
My tank is a 500 ml Fiji water bottle. I can fly for 12-15 minutes with about 1/3 reserve.
At full throttle I would go with at least 24 oz. for a 10-minute flight.
I gap at .0025" to .003". Yes - gap very close to zero. Just to barely see daylight in the gap.
After a good run-in, the valve gap adjustments seem to hold very well with minimum adjustments.
The FG90 is the easiest starting engine I have owned.
I wish my 2 Moki radials would start that easy.
Regards - J Tab
Last edited by Jaketab; 03-08-2023 at 05:09 PM.