I have a 115 HP Johnson faststrike motor (J115GLEDR) that has a problem related to what I'm calling fuel pressure. I always need to pump the primer bulb several times before starting. The motor starts without any problem. Motor runs fine while driving the boat. The problem occurs after I've been fishing for awhile without the motor running. Let's say 45 minutes - 60 minutes. I'll need to give the primer bulb a few more pumps before starting the motor. I've replaced the primer bulb twice with an OMC primer bulb and that doesn't solve the problem. I'm starting to wonder if this may mean that the fuel pump needs to be rebuilt?

This is my thought process, please correct any errors.

Fuel line from gas tank to primer bulb and primer bulb to engine appears fine. No signs of fuel leaking. Since I need to pump the primer bulb, the fuel in the line must be going somewhere. I don't believe it is flowing back toward the fuel tank, the fuel would need to flow "up hill". If the fuel in the fuel line is draining toward the engine, would this mean it is getting past the fuel pump? If all seals / diagrams are ok in the fuel pump would this prevent fuel from "flowing" to the carburetors?

Appreciate any thoughts anyone has on this.