[tentcamper]

These pumps are self priming and can lift water like 5 to 9 feet in a line with no water. It sounds like either the input line is leaking and breaking the suction or the pump has failed. I have had two pumps fail and in both cases they did what you describe. One was from freeze.

They are not that expensive $70. I think Shureflo 2.8 gpm pumps may be hard to get because they came out with the new revolution pumps about 3 years ago. The new 3.0 gpm pump 4008 should have the same foot print, but slightly different. Check the sureflo web site to compare engineering drawings. I think the 3.0 gpm pump is the one you may want to look at if you need a pump. They claim it is more quite and uses less power, plus you pick up 0.2 gpm.