I started using my new Dolmar 421 yesterday. I had a little trouble starting it for the first time, but it seemed to work okay. I ended up throwing a chain and had to get a new one. I put the new chain on last night and went to use the saw today, but I can't get it started. No combination of choke on / off gets even a sputter. It seems to be flood very easily; I see gas seeps from the muffler after about five pulls. I pulled the spark plug and dried it off, but still no go. In the manual they say that the consumer can't adjust the carb, but I see that there is a mixture screw that I can access. I'm using premixed trufuel. Any thoughts on what might be wrong?