System blockage

[shorebird]

After using our waste water deck pump-out for the first time, we now seem to have a blockage somewhere in the system. The holding tank pump, manual, builds pressure when attempting to discharge the holding tank directly into the sea, but operates normally if the y valve is set to the pump-out deck fitting. (dont want to actually pump black water out through the deck fitting, just trying to isolate the blockage.) Now, when I try to discharge the head directly to the sea, it to builds up pressure and wont discharge, unless the other y valve is set to pump it directly to the holding tank. Since the hose leading from the head to the out-to-sea fitting meets it just about a foot before the final through hull discharge outlet, it seems the blockage is within the last foot before final discharge, otherwise, it seems, the holding tank would be blocked, but not the head itself. Now the real problem... I put a "snake" directly into the through-hull fitting all the way to the first elbow, (about 3 feet) and nothing... no clog or blockage. This doesnt make any sense. Am I missing something?

[Sailmonkey]

Yes



But seriously, it sounds like you're turning a valve the wrong way. Draw a diagram with all of the valves ant upload it.

[shorebird]

sometimes just writing it down can do the trick. It finally occured to me, that I was putting the "snake" through the through hull fitting for the sink drain... the head discharge is well below the waterline... what a fool. In theory, I should be able to run the snake through the through-hull from the outside, free the clog, and go on with my merry life.

[bobconnie]

I had a copper tube about 6 ft long, with a air fitting on one end. and a 12 volt air compressor Hook em up and blow weeds out of the inlets and would have worked for this to !! was a handy tool, I used it to blow the crap in the bottom of my water tank out out the lower drain LOL just an Idea

[Swift Drift]

I had a similar clog about a month ago. It was especially awesome since it was during my honeymoon. I ended up taking a broom handle straight down into the waste pump out hole on the deck. From there I worked it around until I found the line out to the through hull. A few plunging motions later, there was a huge cloud of sewage spewing out the through hull into the ocean and all was well.
Not sure if this would all work for your system but it solved my problem.....good luck!