After checking to make sure it has better than 100 psi compression and spark, the first order of business in fixing up most old saws involves replacing the fuel line, fuel filter and installing a carb kit. Between all the varnish and crud that accumulates in the fuel tank lines and filter, and the degradation in rubber/plastic parts caused by the ethanol in todays fuels (that the old saws weren't designed for), it is really false economy not to replace the fuel lines and filter. You may rebuild the carb and immediately have it go bad again by sucking up crud thru the old fuel lines. I know it is tempting to try the easy way and hope it runs OK, but it often costs you more trouble than doing it right the first time. Might want to go over your buddy's place with a six pack and watch him work on the saw. Could learn a lot.