I bought this at a garage sale last summer and I'm finally getting to this thing now. It's in excellent shape to look at, starts on about the 3rd pull and throttles up to WOT nicely. I've only had it running for about 60 seconds (I have to get a bar and chain for it) but it seems to leak fuel from the muffler. I know the air filter is clogged so i ran it with no air filter. I have not pulled the spark plug yet nor have I cleaned the spark arrester screen. Any thoughts