Truck Repair: n-14 fuel problem, air bubbles, gallon bucket

Question
changed a bad ijector and also the fuel filter the truck runs good but after it sits for overnight it will lose its prime and wont start how many o rings is there to change on the filter it came with 3 but i only found two to change it has air bubbles in the plastic canister when it is running what do u think is going on      n-14cummings motor

Answer
the third o ring is for that plastic ring that's at the bottom of the housing I seldom change that one unless theres a problem. the air bubbles tell you that theres air getting in between your tanks and the filter. my next step would be to fill a 5 gallon bucket up with fuel and disconnect the suction line from your pump and hook a hose into that bucket. start your truck if your still getting air bubbles then its between there in the filter if your not its between there and the tank.