I have a question on the oil residue from my DLE 30... My new DLE 30 and my first gas is leaving a heavy thick black residue on the area of the airplane near the exhaust... Is this a result from my oil to gas mixture being incorrect... I mixed it to be 30 to 1 but could have made a mistake on the gas amount...? I am using the oil as recommended... not synthetic... Or could it be the needle settings... the engine runs great and flys great...

The engine has only been run three times for about 6 minutes each time and only flown the last running...