I've had both 2 and 4-stroke engines.

Won't buy another 4-stroke-----ever.

4-strokes DO NOT swing a bigger prop!! Up here in Denver we run an OS91FX with a 14-6 prop. We run a Saito 91 with a 14-6. Same prop. Run a ST3000 (30cc-1.8cu.in.) with an 18-6 or an 18-8. Same prop on a Saito 180. Run an OS61FX with a 12-6 and a Saito 72 with a 12-6; same prop

I have never understood why guys say that 4-strokes swing bigger props. They don't. And noone is gonna convince me of that until I see it for myself.

Yes, you could run a 20-8 or a 20-6 on a Saito 180. And I can also run the same prop on my ST3000. Big deal. Both engines will turn less RPM with the bigger prop. And RPM is power. I don't care what anybody says; these little airplane engines thrive on RPM's. You lug them down and you ain't gonna get any power out of them. Period.

So stick with the 2-stroke and keep it wound up tight. (high RPM's).l

2-strokes are LIGHTER, CHEAPER, and they have a better POWER to WEIGHT ratio.

You ain't gonna get a 4-stroke that weighs 3 pounds to put out as much power as a 2-stroke that also weighs 3 pounds. Period. Power to weight ratio.

2-strokes are simpler too. If it ain't running right, then you check the glow plug(works about 95% of the time) or check the fuel mixture. Very simple.

If your 4-stroke ain't running right; then you might as well pack it up and head for the house. They are not very user friendly when it comes to field tuning. Could be your valves or your plug or your fuel, or a host of other things. Too much trouble to mess with.

Like I said. Stick with 2-strokes and keep 'em wound up tight. Thats where your gonna get the most power for any given weight.

Okay, I'm off the soapbox now. Sorry.