Been doing some work on the 73, the piston and cylinder are good. I'm having trouble with the recoil engaging so it is off and getting some lub, everything is so dry and stiff. I filled the engine with fuel mix and turning it over by hand. It is getting much easier to turn. The air filter is in decent shape but some of the flocking is thin. The inside of the fuel tank is like new with the felt pad still nice. Oiler works. The chain is so far stretched out that I can't get it tight enough. Where can I get chain that is 5/8" . The sprocket is good.