Trim tab pump 228

[Johnny Dollar]

having an issue keeping my pump primed for trim tabs losing prime attached to lines i pull the motor then prime it off the lines test it before installing lines and it is blowing air and spitting pump is brand new any suggestions or ideas?
We had it working then i decided to change the hydraulic pistons one was stuck in down position got the new ones to work once can't hold prime with hoses attached or with hoses disconnected

Thanks

 

[DennisG01]

having an issue keeping my pump primed for trim tabs losing prime attached to lines i pull the motor then prime it off the lines test it before installing lines and it is blowing air and spitting pump is brand new any suggestions or ideas?
We had it working then i decided to change the hydraulic pistons one was stuck in down position got the new ones to work once can't hold prime with hoses attached or with hoses disconnected

Thanks

It's hard to follow what you are saying - can you please edit and break-up the run-on sentences?

 

[glacierbaze]

If they are Bennett, they are self-priming, by running the tabs full up to full down 3 or 4 times, with all lines attached.

 

[seasick]

If you are referring to trim tabs attached to the transom and by losing prime you mean that they do not stay where set and retract over time, then you have either of two things going on.
The lines or cylinders have a leak. That should be easy to check or if no leaks, then the check valves on the pump are not sealing. Those are ball bearing check valves with an electric solenoid. The solenoids can be removed by unscrewing keeping a close eye on that operation to make sure you don't lose the check ball. If the fluid is dirty a small speck can get wedged in the check valve causing it to not seal 100%

 

[Fishtales]

I'm guessing a line leak. May need to come up with a way to pressure test them independently from the pump itself.