AC raw water pump prime

[Dallasron]

So after I installed the new AC unit (MarinAir 16,000btu) It is always a pain to get the pump (Little Giant) primed to push the water through the unit.

If I leave it overnight the next morning it is all good to go and as soon as i turn it on the water is pushed out the hull.

Should I maybe be looking to install a check valve?

Thanks in advance
Ron

[rslifkin]

Those pumps are generally not self priming. Is the pump installed below the waterline with no high spots in the plumbing between the thru hull and the pump? If not, the plumbing layout will need to be corrected for it to work reliably.

[SailingHarmonie]

Originally Posted by rslifkin

Those pumps are generally not self priming. Is the pump installed below the waterline with no high spots in the plumbing between the thru hull and the pump? If not, the plumbing layout will need to be corrected for it to work reliably.

This! The only change I would meke to this comment is to change

Those pumps are generally not self priming.

To:

Those pumps are never self priming.

[CaptTom]

I just mentioned in another thread, on my last boat I put a "T" fitting at the pump inlet, with a hose going straight up above the water line, with a valve on it. Opening the valve primed the pump. This assumes the pump is below the waterline.