I am new to gas flying and I have a US 41 on a Giant Big Stick. Question: How can I tell when the mixture (both high and low) is correct? Is it just like a glow engine? I use the pinch test for a glow engine (pinch the fuel line if the engine cuts out for a second it's too lean, if it doesn't change at all it's still rich). Does this work on a gasoline engine? I have noticed that if it is too rich, it sounds like it 4-cycles like a glow engine. I leaned it enough to get out of that but even when I pinch the line the RPM still doesn't change. Is it still too rich? Incidentally, I am getting about 7500RPM with a Zinger 18x8. Should I be getting more power?

Thanks,
Brian

Do a search here on tuning a gas carb. We have discussed this in great detail. Once you have it adjusted do a plug check. The plug should be a light tan if it is adjusted well. I have a 44cc Echo conversion I did and it swings a Menz 20X8 at about 7100 or so. I would think you would find your engine will pull harder with a little larger prop.