225 efi merc primer bulb not getting hard

[gasguzzlrs]

I have a 25' trophy with dual 1998 225 efi mercs. One primer bulb will not get hard. Even when I swap fuel lines from tank to motors. Motor still runs well on the trailer i havent had it in the water since i noticed this. Any help would be great.

 

[Docksidemarineservices]

Pull off the mechanical pump on the engine, leave the lines hooked up and squeeze the primer, look for fuel leaking from the pulse port. If leaking, replace the mechanical pump.