When my last mower finally quit running, a friend gave me her used mower. She had stopped using the mower a couple years earlier when she started hiring a yard service to cut her grass. The machine had been working fine the last time she used it.
The lawn mower looked great. Well, there were a few rust spots. It had been stored in a shelter. I don't know a great deal about mowers, other than how to cut the grass with one, so I took it to a lawn mower service center to see what it needed.
There were a couple small issues, but the biggest problem turned out to be the carburetor. The mechanic thought he could rebuild the carburetor with a kit at first, but when he did this it was still leaking gas.
Eventually he replaced the piece with a new carburetor. I hadn't planned to put that much money into the lawn mower parts and repairs, but once I started I was stuck. I could have bought a new mower for a little more than I paid for the repairs on the old one.