Primer Bulb is failing

I have a 1997 Johnson 150 FastStrike. My primer bulb fails because pressure is building up between the bulb and the engine block. I think this happens when the sunlight warms up the black engine cowling on hot sunny days(or it seems). The pressure is so high that I can not pump the bulb. It seems like it is full of air and relatively hard (not the normal squishy sound of gas pumping thru as i squeeze it). To fix the problem, i pull the bulb off and it release the pressure then i reasemble and it works fine.

Do you have any experience with this problem.

You need to go back to basic chemistry, when gas gets hot it expands and fill voids, If the motor sits in the beating hot sun then of your fuel lines will heat up and have no where go but back down the check valve. The fuel system is based on a vacuum pull system not a driven system.