Please keep in mind that when you deal with any materials that come in contact with gas or oil, they must be made for that reason.
Most items you find in a hardware store will deal more with contact with water.
If you go looking fro replacement seals, the auto parts store should be the first stop (lawn mower shops are even more likely to have stuff to use)
PS sorry if my comments to joseph ho complicated this thread. His choice of language seemed a bit much.