strato911, sorry about the late reply. I kinda just forgot about about this thread. I was going to say that your 25cc Poulan should fly your "Blue Heron" just fine. With that much wing and at 10lbs, even a stiff piece of carbboard will lift off.

Not to doubt your RPM numbers, but that is one stout 25cc weedie conversion!!!! My twin-ring G-23 and single-ring 25.4cc Kioritz don't get anywhere near those numbers - and they are both "Pro-grade" weedies. If you can verify that the numbers are correct, I'm buying one tomorrow!! Try a 16x6 or 16x8 APC, and tach it in bright sunlight. I know my cheapo tach gets flaky when the sun starts to fade toward dusk. The fact that it fluctuates 1400rpm kinda makes me wonder.

Also, AFAIK spark ignition gasser 2-stroke engines do not "4stroke" anywhere near as much as glow engines do. That spark plug fires every up stroke regardless, so combustion happens pretty much every time. Now when the mixture is overly rich, it might "misfire" every so often, but I don't think it can "4-troke" 80% of the time. That would mean that the darn thing misfires 40% of the time.