R V water pump

Sucking air i on suction side of pump

Could be loose/cracked fitting at pump or pump casing
Could be loose hose clamp on suction line
Could be cracked suction filter/strainer Or not screwed on tight
Could be sucking air thru winterizing valve/line (if you have kit installed)

Somewhere on suction side of pump is allowing air to be drawn in when ump is running.

Hot water tank full?

2oldman wrote:
Hot water tank full?

Yes the hot water tank is full , trailer is 4 years old .

Sucking air between the tank and pump. If you have a winterizing tube be sure it is tightly closed.

Tank vented properly? Does the pump run smoothly, or off and on?

2oldman wrote:
Tank vented properly? Does the pump run smoothly, or off and on?

I think tank is vented & I put a cork in the suction line for winterizing. Pump runs smooth. I'm puzzeled

Uually wrote:
I think tank is vented

Ok, because if it's not, it will do what you describe. But it wouldn't do it right away, it may pump fine then start sputtering.

Uually wrote:
I think tank is vented & I put a cork in the suction line for winterizing. Pump runs smooth. I'm puzzeled

Crack in filter/strainer prior to the pump?

Crack in pump housing?

Crack in line between tank and pump?

Could be a bad install.
On our TT the pump was mounted 14 feet horizontally from the tank. This caused all kind of priming problems and I often had air in the lines. It took lots of running to get it out and then after sitting the air would come back. Think about holding liquid in a straw while you have your finger on the top. Turn the straw horizontal and the liquid starts drizzling out even though your finger is still on the top.
The pump manufacturers say to have no more than 10 feet between the pump and tank but I can tell you it works better the closer you get.
I ended up moving my pump right over the tank and it works fantastic now.

I think you need to be a bit more "specific" with your problem. Are you saying that you get "continuous spitting" when you leave the tap open "forever" (ie. a long time) in that, you never get a continuous steady flow. OR are you a saying that any time you open a tap, you get splitting but eventually get a continuous flow.

IF you never get "steady flow", like cause is a blocked intake or pump problem. IF you always get "spitting" during the initial open, then like a pump problem possibly related to a failure of the oneway valve / seal at the pump.

IS your pump always switched on? IF so, does it run when no one is using any water? If its isn't always switched on, when you do switch it on, does it initially run?