If your oil smells like gasoline, the carburetor is bleeding fuel past the float needle. It has had fuel sitting in it for extended periods between use or the float needle is bad.
The oil needs to be changed, and the carburetor properly cleaned... Especially on the inside.
In the future, it is best to run the fuel completely out of the tank and carburetor at the end of the season.
Also, I advise using a fuel stabilizer like Ethanol Shield or Marine Stabil (The blue one)