I have an echo conversion that I think is a 25cc (measured bore x stroke) with a cdi ignition and an 11mm walbro carb. I'm getting 8600rpm with an APC 14x6 and 8000 with a Topflight 14x8. I know the APC puts out about 8.5 lbs of thrust at 9400 on an O.S. 91 4stroke, and I'm looking for 10 - 11 lbs from this echo. My question is what are some of your rpm and thrust readings with various props? I'd like to know if I can get this kind of thrust from this engine before I go out and buy a handfull of $15 props to experiment with.

Thanks.

A 15 x 8 or 16 x 6 APC prop should get you where you want to be.

AV8TOR

If you need more thrust i would be looking at a bigger diameter prop, even on my 21cc weedeater i was running a 16x8 (7000rpm) and a 17x6 ( 7200rpm), 14" is just too small for an engine that size especailly if you are needing more thrust.

Thanks, guys. I'll try that this week.
Looking at putting this on a Funtana 100.