Good for you, I would do the same, not many shops will take the high road like you are ?It belongs to an older couple (80+) and i have worked on other stuff for them before. As far as i know they really forgot why they parked it. If i had asked for money i am sure they would have paid me but since i neglected to check it before i started servicing it i feel it is on me. They gave me the mower so i might use the carb or something.