I have a few questions about my O.S. .40

I have been adjusting the mixutre and needle valv lately. After a few flights i noticed that fuel was begining to "cook" and turn brown on the engine. I was told once that this is normal and another time that this means it is running too hot.

I have plenty of residue along the side of the plane but there is also some brown residue in it. Is this ok? (I was told this is fine and is only un burnt oil cleaning the engine out)

Also, at the end of the day while flying and tweaking the engine all day, I noticed that the engine would bog down when I opened the throttle all the way. It died twice in air. I was told this is a simple needle valve adjustment.

Anyone mind telling me the adjustments I should make?

WAY TOO LEAN!!!!

You are cooking the motor, you need to open up the needle some.

You should not need to play with the mixture during the day. Once, maybe.

The reason it dies, it becasue it leans out in the air and that is the reason the head to turning brown.

When you adjust the needle on the ground, use the pinch test. Pinch the fuel line. If the RPM's drop, you are too lean. When the motor is propperly tuned, when you pinch the fuel line, the RPM's should jump up. Leave it there, do not adjust any more.

I use the pinch test for low end only. An easier way to do the high end is to simply have someone hold the plane while you bring it to full throttle. Once you reach max RPM, point the plane straight up. You may get a slight increase in RPM, but you should NOT get any decrease. If you do, it's too lean.

As Minnflyer said, raising the nose at full throttle is a better way to test high speed needle settings. (In my opinion.) And if it's dieing in the air it's probably too lean.

As YNot said, you should not be playing with the needle(s) all day. Once set, I seldom touch my needles from one week to the next. The only time it's neccessary is if the weather changes substantially. Like a LOT more hot and humid, or it gets much colder.

All engines will develop a dark brown reidue over time. It's the unburnt castor oil cooking on the engine, and it's natural. If it's developing quickly (after a few flights), it could be a sign of running too lean however.
Dennis-

I believe i'm running too lean then, didn;t thick i would be runnin that lean though as much as i richened it.

The the brown stuff cooking on the engine has acumulated over a few days of flying.

When you turn the high end needle in, to max rpm,turn it back out a little until you notice a little drop in RPM. Then do the nose up test. Change your glow plug , excessive heat and residue from the breaking in process will shorten its life. better safe than sorry. I learned from the school of hard knocks if it glows it does not mean its alright.