Holding Tank Pump Out Not Working

[pma_foyl]

I have a manual pump out for my holding tank. Till recently it worked flawlessly. This weekend while sailing offshore, I tried to empty it and it pumped bit, then stopped. I thought perhaps it was having "gravity issues" with the port heel, so once we tacked I tried again. No dice. I could see the "stuff" trying to build suction, but ultimately not being able to get past the "out" fixture on the tank. I suspect the "pump diaphragm" since it is clearly not developing any pressure or sufficient suction (though it appears to be trying). Could there be anything else preventing the build-up of suction? Could the vent be causing this? Any other ideas, before I take the pump apart. Thanks.

[elhanley]

If you can start it moving, but run out of lift, I''d check the vent first, or if it is not a big deal, simply replace it.

[pma_foyl]

What would I be looking for when I check the vent?? What might he problem be?

[Tom3]

If the vent is blocked the pump will be trying to pull against a vaccum and it will fail.

Clean the vent with a screwdriver first and see if the pump works.

[sailorrest]

I assume you also have the ability to pump the holding tank out through a deck fitting? If so remove the cap from this fitting and try your manual pump. This will eliminate the vacumn caused by the blocked vent line.

If this works recommend you remove the vent hose, clean the skin fitting and install a new hose.

Tremendous hydralic pressure builds in a holding tank that is over filled. The "stuff" attempts to exit through the vent and in compacted in there like cement.

Good luck and maintain that 3 mile offshore position.