The joke is on me!

[Peggie Hall HeadMistress]

Funny thing about water...it only wants to run downhill. You aimed your discharge fitting to run straight UP, so any water in the bowl would have to run UP hill to drain (it's not a siphon) out of the bowl. However, as your new joker valve becomes worn, any water left in the discharge fitting or in line above it will start to seep back downhill into the bowl...more quickly as the slit in the valve gradually gets wider due to wear.

 

[JamesG161]

Funny thing about water...it only wants to run downhill.

Well I couldn't resist. How to make water run up hill without electricity or siphon. Good for you end of world prepers or Zombie fears.

Funny thing about siphons, they work in two directions.
Jim...

 

[Peggie Hall HeadMistress]

You obviously have WAAAAAAY too much time on your hands, James!

 

[JamesG161]

You obviously have WAAAAAAY too much time on your hands, James!

Well guess what? As a young engineer in training we had to learn about all types of pumps. The above is called a Hydraulic Ram pump.

My all time favorite is an Cottrell Pump (peculating coffee maker).
https://en.wikipedia.org/wiki/Ebulliometer

Does everyone remember the toy bird that bobbed it beak in some water and would rock back and forth then return to dip its beak of another drink? No power? Perpetual motion? ( evaporative cooling pump )
Dang I found that on the web. https://en.wikipedia.org/wiki/Drinking_bird Ya gotta love finger tip info.

For the love of the heart, blood and gastro systems.
Peristaltic pumps
https://en.wikipedia.org/wiki/Peristaltic_pump

@Peggie Hall HeadMistress if you read those links you do have a lot of time on your hands.
Jim...

 

[RHUMB RUNNER]

The 90 degree bend just runs up to the loop that the factory installed. This loop in the discharge hose is at the top of the bowl.

 

[Peggie Hall HeadMistress]

This loop in the discharge hose is at the top of the bowl.

That's way too low for a vented loop on a sailboat. A vented loop needs to be at least 6-8" above waterline at any angle of heel...which, on most sailboats puts it 2-3 feet above the bowl. (see photo)

And btw, if your Quiet Flush is the sea water version, there should also be a vented loop in the intake line that's the same distance above the toilet as any loop in the discharge line, with electric solenoid valve installed in it that's wired to the flush button. However, if your toilet is the version that uses onboard pressurized fresh water, no intake vented loop is needed.

 

[RHUMB RUNNER]

This a fresh water head, their isn't a vented loop in the intake or the discharge. All works fine with the new joker valve.
Thanks,
Gary