Help needed with black water gate valve.

I have read about this stuff called Break Up Plus.Link to BUP. I plan to get some at the RV store next time I go there. They have a web site so you can read about it. Also, maybe its not paper in the valve. The rubber side seal might be ripped causing the blade to bind up. If you can dump the tank and have access to the valve it is easy to remove. 4 bolts and spread the pipes a little and it should slide out.

I have a flush king and so far it hasn't worked. I have tried filling the tank to the brim and dumping it quickly. I also tried to dump it with the valve partially open hoping the turbulence would clear the paper. So far nothing. I might try using chemicals to dissolve the paper. In the past I haven't had any luck getting chemicals to actually dissolve paper. Anyone know of a chemical that actually works?

We had that and used the flush king after dumping. It cleared the paper or whatever off the valve and it quit leaking and shuts fine.

Here is another thought, I have a leaky tank valve I believe is the black tank. To replace it means dropping the plastic first. Not something that thrills me to spend a weekend doing, so I picked up from CW a valve that twists on the end of the pipe. It wasn't too costly, works so good it.may be next year before I bet motivated to fis the problem.

This is probably my first post recommending a Flush King as I think they are potentially extremely wasteful of potable water. But in your situation this might work.
Link

Hook the flush king onto you dump outlet, attach a garden hose and a sewer hose. Leave the Flush King valve open and open the original black drain tank. Let the tank drain. Now turn on the garden hose and close the Flush King valve but leave the original valve open. This will flow water back into the tank and hopefully dislodge the obstruction. Fill the tank about half way and then open the Flush King to drain the tank again. If you can't get the plug cleared after a few fill/drain cycles, at least your tank will be fairly clean for the ensuing dis-assembly of the original valve.

flush and work the valve x 1000. If you have a valve on the end load it with chemical and let it dissolve a few days then see top advise. Good luck!Let me know how you make out.

one thought that comes to mind is to completely empty the tank, flush it out a few times with water hose filling up the tank each time to get the most flow through the valve. If that doesnt clear it the trash out then try running the hose up from the bottom.. By this time the tank should be fairly clean. Maybe a direct stream on the trash might move it. Of course I would wear rubber gloves once the bottom route is taken if needed. Stand back as you may get some other trash out too unexpectedly.

One of those caps with garden hose thread and a double female adaptor and back flush with a garden hose???

(hopefully you are not brim-full, of course)

The only other thing that comes to mind is an old fashioned plumber snake and some sort of pasture or huge lawn where mother nature can take care of things without impacting a homestead...