2004 115 Four Stroke Merc Starting Concerns

I have a 2004 115 Four Stroke Mercury. It's on a 18' Kenner Vision. I have owned boat and motor since new. I have starting concern it cranks but will not start. This has happened only 3 times and happens after a long run around 10 miles or so. Today I ran down Chocolate Bayou and fished a few areas. We ran back to the boat ramp and after cleaning fish and getting the trailer in the water the motor would crank but not start. I checked the primer bulb and it was hard. I did give it a pump but it still would not run.

Any Ideas??? My first thought is to go to Evans this fall when deer hunting starts up.

2004 115 Four Stroke Merc Starting Concerns