Ok...
The engine is a GMS .47 with maybe 1 gallon of 10% omega run through it. I bought it from Mecoa's auction on ebay for less than 50 bucks NIB, and it is one of the best running engines I have ever seen. Straight out of the box, I carefully ran three tanks of fuel through it before it ever got airborn. I know its not fully broken in yet, but here is the issue at hand.
I mounted it to my trainer, swinging a 10x7 prop and had a handful of flights on it when one day I lost radio contact with the plane right after putting it in a nose dive and applying full throttle...the plane was turned into firewood and I had to dig the engine out of the soft dirt. Thankfully I was flying over a freshly plowed field. I blew the dirt off with an air compressor, dismantled it, and hosed it down with WD-40(bearings, crankshaft, etc...) I blew the gunk out again with the air compressor and repeated the process two more times before putting it back together.
Now I have this engine mounted on a Super Sportster swinging an 11x6 prop. The engine still runs great and will idle real low for a long time and not even hiccup when going to full throttle. Given the price I paid and how good this engine runs, I am very partial to it.
The problem is that the exhaust oil is very dark...well its black. Today while flying, my throttle arm loosened up on the engine so I had no control of the engine speed(yep! you guessed it- full throttle again) so I had little choice but to fly the plane at WOT until it ran a full tank out of fuel. When I deadstick landed it, I realized how dark the exhaust oil is (it shows up good on white monkote)
My question is this- is this normal or has the engine sustained more damage than I thought. Is it a mixture issue or what? Any advice on this is greatly appreciated as I am not very experienced with glow engines