The problem I had last year which I failed to explain in my earlier post was the gasoline in the filter under the cowling was vaporing off due to the heat of the summer and the heat of the engine combined. Heaven only knows where the gas went being as my engine is a fuel injected four stroke.
I spent four days on the water 3 weeks ago without a problem. Last summer my first instinct was the primer bulb so I replaced a new bulb with a new mercury bulb and the problem still existed.
Fuel pump is a possibility but I would lean more to having a leak in the fuel line. If you suck any amount of air in you will have headaches.
Good luck with finding the problem which I hope you do quickly to avoid missing any days fishing.
Bo