Hi everybody,

I was recently given a Great Planes 1/3 scale pitts special with a 41cc US engine. This is my first gas plane and I have a few questions. First of all, how should I break in the engine? Is it similar to the procedure used for glow engines? There was no manual with this engine, so I'm not real sure of what I'm doing. The only information I could find was a two page reference sheet at the US engines site. Anyone know where I could download a more detailed manual? Also, how big of fuel tank should I use and is there any brand that is better than another? Thank's for your help.

Elijah Brown

Start it, tune it, (if needed), fly it. There is no need for a long breakin period on a gas engine. Use a 16-20oz tank with stopper for "gas" engines. Use Tygon, Aerotrend, or neoprene fuel lines.
I just sold a new US-41, and the only manual it has was a couple of pages of general info.

Any other information?

18-10 prop.

I use the Poulan synthetic oil.

I think a small can makes a 50:1 gallon of gas/oil.

You also may want to run about 40 oz of gas mixed at 25:1. This will help the ring life in the long run. The Poulan synthetic is very good. Don't run rich rich like a glow engine. Unburned fuel will coat the cylinder walls and scuff the rings.

US Engines recommends 32:1 as the fuel/oil ratio. I use Echo 2-cycle oil with regular pump gas in my -41, runs great, better and better each time I fly it. I have run it at 40:1 with no problems, but 50:1 might be a bit light on the oil. Do you have the spring starter on yours?

I use a 16 oz. tank and get about 15 min. flying time with a small reserve. I have tried props from 20-6/10 to 18-6, but for my plane (22 pounds) 18-10 seems best.

Will run forever on 40-1 mix. Lean high speed jet till it peaks, bach out till you can hear it slow down a bit. Adj low jet after heated up and lean out till it hesitates on acceleration. Back out till it doesn't hesitate. After plug carbons up, should be a tan brown colour. Hope this helps