Hi there, I am helping restore the old barn of a friend. During the clean up we found what appeared to be an old chain saw. It was caked under about 1/4 inch of dust, gunk, and crud. It was in seriously bad shape. He said that if I can fix it, I can keep it. “Sure!” I said. I cleaned it up (a lot!) bought a new fuel line, new fuel filter, and new spark plug. I cleaned it with some simple green and lots of water. After drying and putting it back together it looked quiet nice. It is a Stihl 021. However: It does not run. I put the cord and it has compression. If I put a little gas in air filter/carburetor it starts up, but appears to be on full throttle and runs really fast for about 2-3 seconds. Then it stops. It also smokes a bit when it runs for those few seconds, but since I out the gas in manually I am not sure if it is the carb adjustments. Any help is VERY welcome. I have been trying to get it to work for weeks now and cannot figure it out. Even a simple “I don't know” is better then no answer.