I have an OS 61 fx in a revolver and it doesnt seem to be getting the rpm out of it that it should. Im running a 13x6 prop. I have also tried a 12x8. The plane flies slow. I would have thought it would scream with a 61 in it.
My main concern is that there is no difference in rpm between 3/4 and full throttle. Why is that?? Im watching the carb barrel move and not going by the movement on my radio. The HS needle is out about 1 1/2 turns and the glow plug looks good. I have about 1 1/2 gallons through this engine. I fly at about 4500 ASL, so I usually go up in engine size for all of my planes. Im just suprised its as slow as it is. My mustang PTS is just about as fast with the evo and a 11x6.
Any thoughts or input would be appreciated. The plane does fly good, but I expected more from it with that size engine.