Head Pump Issue

[captainpat]

Anyone – why would there be back pressure when pumping DRY BOWL only? No back pressure when pumping wet! Jabsco claims that after checking the HT vent (not an issue) and the joker valve (also not an issue) that there must be a clog in the hose. My thinking is that a clog in the hose would also effect the wet bowl pumping.

 

[Bill Roosa]

Check the dry wet switch. You may have to set it to some intermediate value. If that does not help then pull the top of the pump off. There is a valve under the top that controls air/raw water into the pump.
When putting the pump back together note that the first time the screws where put in they cut their own threads. If you just slap it together and the screws try and cut brand new threads into the plastic it will crack the plastic = $$$$$ to fix. Hand start the screws and use a light touch to determine when the screws are going into their old threads.

 

[timvg]

And sometimes, it's just easier to replace the pump. Even for this sometime mechanically challenged sailor, it's about a 10 minute job.

 

[Ariel]

Is the inlet seacock open?

 

[Ron20324]

As in #2, the switch is not operated fully to dry sometimes, but not most of the time. I tell my crew if they meet resistance when pushing the handle down on 'dry bowl', the switch is partially open. Flip it to wet, then back to dry and it works as it should.

 

[captainpat]

Thanks all. As it turns out the problem was with the Top Valve Gasket (Pt #: 29042-0000) which was replaced.