Your injectors didn't get clogged from bad gas, you got water in your tank. The marina is taking you if they say it's from the ethanol attracting moisture.
Water and fuel don't mix, they separate. At night, moisture condenses on the walls of the fuel tank and then runs down to the lowest spot (very close to the pickup). In humid climates this can be a nightly process. If you want to keep it clear, fill your tank when you put the boat up. No air on the tank walls = no condensation of water in the tank.
Capt Sam is right about ethanol attracting water. I dont think in two months it would cause that many problems though. I can leave gas in my dirt bike or street bike 6 months and not have issues with it. I started a 72 chevy truck with almost 2 year old gas with no problem. Houston is also pretty humid. Im not debating that the old gas was breaking down or anything like that but 2 months does not sound right. Most likely already had build up in the system for it to give problems after 2 months.
This is one of those questions that everyone has a differant answer.