Here's a problem no one needs...

[Ncbob]

Jon, then we both understand...as Tom Cruise said in the movie, "Yes sir, Crystal Clear"
how easy it is to open your mouth and convince the world that you don't know sheep $hit from apple butter about anything you're doing...right?

As always, with tongue-in-cheek......

Bob

[gumpy]

Bob,

On your little hole you drilled in the elbow...

you might be able to take a solid PVC plug, and ream the hole until the plug will just screw into it. Put a generous amount of PVC glue on it and screw it into the hole till it's just inside the pipe. Let it set, and cut off the plug, or just leave it be.

Might work, and save you having to replace the elbow and fitting underneath. I see you used a rubber connector on the elbow, so
can save the flange on the valve.

craig

[Ncbob]

Funny how great minds think alike, Craig...I was tossing some ideas around to that same end last night. I'm not sure if I brought my 3/4" NPT tap with me, certainly wouldn't buy another one just for this job...but installing a plug might be the best way just in the event the slide valve really failed one day.

Naturally, the P/O installed the valve with the screws facing aft....

Think ahea
              d.

Bob

[gumpy]

Another idea is to just cork the hole. Find a wine and beermaking supplies shop and purchase a solid rubber stopper that will fit the hole. Probably a number 5 or so. Stuff it in the hole and kind of screw it in. It will expand slightly inside the elbow as it passes through the hole and will still be removable. Might have to change it every 5 years or so.

[Dreamscape]

Until you decide what to do....Duct tape would probably get you by...