ORIGINAL: RoNeRiC

>What causes the engine to hesitate when going from 1/2 to full throttle
>during flight? Not very quick response time.

The low end (idle screw) is not set properly AND/OR you may have an airleak. If you have bubbles in the fuel line while transitioning you have an air leak in the fuel line. The idle screw plays a large part until you get to ABOUT 1/2 throttle.


>And when I shut off the engine via the throttle trim and the carb is completely
>closed, there is fuel sitting in the carb. I read the thread on engine tuning
>and what is the 2 stroke and 4 stroke sound I'm looking for?

The 2 stroke sound is the "screaming" of the engine. The 4 stroke sound is more like a "blubbering" - similar to when the engine is very rich and at an idle. When you go from the 2 stroke to the 4 stroke the change in sound is distinctive. The engine smooths out. It is kind of difficult to describe. Once you hear it though, you will know the difference.


>How do I know if it is too lean (too lean as in damaging the engine).

With the engine at full throttle, point the plane straight up. If the engine dies, it is too lean and you need to open the HIGH SPEED needle valve a little (richen it up). I suggest doing this in 1/8 turn increments. If the engine speed stays the same, or picks up slightly, the HIGH SPEED needle is set OK. Remember to set the high speed needle about 300 rpm LESS than wide open since the engine will "unload" in the air and speed up a little.

FWIW - I recommend using SOME castor oil (about 3 oz per gallon) in your fuel. The castor helps protect the engine from lean runs and the internal residue helps protect against rust. If your fuel is a 100% synthetic oil, I would add some castor oil. If it is a mix of synthetic/castor oils, see what the percentage of castor is and then ask if any additional castor should be added.


Can't get to the field today so I was going to try to work on the engine but I am a complete noob.