Loosing Fuel Prime

[alupinit2]

Fuel bulb loosing prime within and hour or so. Fuel is not leaking back into tank -new OEM primer bulb and anti siphon valve.
Re-prime bulb and everything okay until I stop again for an hour or so. Any ideas would be appreciated.

2002 Johnson 115 HP.

[boats.net]

Check for fuel or air leaks at fuel pumps, fuel filters, hose connections and carbs on engine.