Black tank pumpout

[gwwalsh]

It seems that nearly every time we try to pump out a vacuum forms after a minute or so, thus preventing the waste from being pumped out. We are pretty sure the exit tube is free of clogged material, but the vent tube seems to be the culprit. We have squirted water into it, which seems to work for a bit, but then the flow stops again. Any ideas out there? Thanks!

 

[baz]

Have you ever over filled the waste tank ? If so this could mean some junk could be lodged in the vent tube.

It sounds like clearing the vent tube with squirting some water into it does clear the issue temporarily, so a more thorough cleaning appears to be something worth doing.

Remove the vent tube from its transom mount and use an extended/straightened wire coat hanger down the tube to clear it out. Reattach and try pump out again.

Whenever I pump out I always fill the waste tank up with dock-side fresh water to get the waste tank material mixed up and then pump out. I then fill the complete tank up again with fresh water and pump out for a second time.

I will also squirt some dish washer liquid into the head and flush that through a few times before pumping out. This helps clean the lines and the tank itself.

 

[gwwalsh]

Thanks for the reply Barry! We have not attempted removing the vent hose to clean it, but have done the multiple rinsing previously. I am wondering whether a larger diameter vent tubing would solve the problem.

 

[Dog Islander]

If you have an inline filter it would be located in that vent line. The vents have been known to cause enough restriction during pump out to cause some vacuum buildup in the tank. If you don't have a filter, then a kink or other obstruction is likely the cause. The vent line on my R27 is relatively easy to remove. I'm not sure if that's the case on your boat, but I hope so. Good luck!

 

[gwwalsh]

I don't know either, but will check it out when we return from our rV trip to Lake Chelan and Lake Wenatchee this next week. Thanks!

 

[Todd]

Check the vent line for kinks and or a soft spot in the tubing. It is possible the line vents the pressure of a flush ok but collapses under the suction of a pump out.

 

[gwwalsh]

Another idea that didn't occur to me. Thanks!