Check the spark arrestor screen in the carb, it may be plugged with carbon.While you have the muffler off, check the piston and cylinder for scoring or galling (aluminum transfer)

The spark arrestor screen is in the muffler, not the carb. Have you adjusted the carb mixture screws? Start with 1 1/4 turns out from the bottom on both screws. An old saw like this will need at minimum: carb cleaning with new parts kit, fuel filter, spark plug, fresh mixed gas. Most saws of this vintage will need the crank seals & fuel lines replaced as they dry out, crack & suck air.