ORIGINAL: rccub

i have a zenoah g-26 engine that is mounted on a sig rascal 110. it seems to run ok.(bought everything used), but it leaves a black sticky residue on the plane. the settings on the carb are a little rich, but not excessive. is there too much oil in the gas. the guy i bought this from gave me a gas can with the mixture already in it, and said this was what he had been using. he says the engine is new, with about one half gallon thru it. again, it seem to run well, although it is a little hard to start. i have to use a starter, it wont start by hand. sorry for being so winded, but this is my first gasser and need help. thanks.