Most of the hard starting, vapor locking problems were from th 50’s to 60’s saws, being used all day by pros. By the time I got into the business, in 1972, the vapor locking problems were pretty much over. If we had any starting problems the saw went to the shop for a tune up and came back running. Big difference between using a saw all day 5 days a week and the hobbiest I’ve become. Now a days if I have a starting problem my first guess is fuel, then ignition. Most of my saws sit for months, even years, between starting. The old saws are for play, I’ve got new saws to beat on.