Don't worry about the engine running a little rough. It will take a minimum of 11 to 12 gallons before it breaks in and smoothes out.
My Bergen gasser has over 40 gallons of gas through and it runs pretty smooth. The lower part of the tail fin will vibrate about 1/8".

Blade selection is very important with the gasser. Use a very heavy blade. So far the best blade that I have found is the 680MM MS composite FAI PRO. However I emailed Vic at V-blades and he says that he some heavy 3D Blades. The lighter and longer blades will bogg the engine. With the MS 680's you can tumble many times with dropping power.

I believe the correct oil ratio is 5 ounces to 1 gallon of gas. It is written down at the barn so I would have to check on it.

Something else to look out for is the location of the tail drive shaft bushing. Mine had a vibration that drove me nuts for a long time. Recently the tail boom was removed and what happened was the tube became resonant and was hitting the inside of the tail boom. So try moving the bushing closer to the driven end.

If you need any upgrades try www.bergenrc.com he has a cooling system for the excel gasser.


Fred