I have a weekend warrior toyhauler The shurflo pump never shuts off. Here is what I have done Swapped out for a new shur flo pump, replaced line from tank to pump all new fittings, water in tank. primed every way I can think of, check city water gravity feed vavlve door . If I remove the intake line from the tank to the pump and put on a makeshift fitting to a water bucket it stops. That"s why I replaced the tank line. The Pump does not have a strainer in line and the tank is not plugged up. Does a strainer do anything to help maintain the prime and pressure? any help would be appreciated