I have an outboard which I seldom use. When I exchanged the gas, a year old, I had leaks in the relatively recent hose and squeeze bulb. The culprit appears to be using gas with alcohol. If you run your engine frequently and the fuel goes thru it's apparently not a problem. Only when the gas sits for a long while.
Gotta use the ethanol free stuff. Usually available around the marine environment. Heck it's even better to use it in your car as well but harder to find away from the coast. Kinda of a shame we take up so much farmland just to burn it in our cars. Jus my two cents worth.