my NAA owners manual says I have this valve in my hydraulic pump for PTO.
It suggests that I can turn the knob on the end to adjust the flow of hydraulic oil pumped to the lift cylinder. How do I access this knob?
My backhoe runs off a separate pump in front of engine, not from the PTO, so apparently I have 2 systems. It has been suggested I decrease the flow, and maybe turn off the PTO system to get the backhoe to operate correctly.
Any help is help indeed! Thanks

The Hy-Trol valve is only on the NAA's original vane-type pump.

Many of the vane pumps have been replaced with piston-type pumps over the years.
...The piston pumps do not have a "Hy-Trol" valve, so there is nothing to adjust.

Both the vane pump and piston pump are attached to, and driven by, the engine. ...They do NOT use the PTO for power, or supply power to the PTO. ...They only power the 3-point lift.

What make/model backhoe do you have? ...Does it have a separate reservoir for the hydraulic fluid, or is it connected to the tractor's hydraulic system?

What do you mean when you say the backhoe does not operate correctly?

Thanks for posting. Yes you are correct, the pump had been replaced, no hy-trol.
The backhoe apparently is chinese made, through Harbor Freight, I believe. Came with the tractor, but separate, It does have separate hydraulic fluid reservoir but did not appear to be full so I added fluid to it.
When I attempt to dig with the bucket, at ground contact the whole unit raises the 3-point creating a surprise momentary ride, until released.

Hope this helps.........Ed

Thanks for the pictures; The close up of the hy-trol really helped. Unfortunately a previous owner changed it so there is no control knob. Also the selector lever for constant draft appears to be stuck. I have a local mechanic who owns tractors and he promised to come look at it and educate me more.