If you're asking specifically about the clutch lever for the PTO, it should always be down when the PTO is in neutral. The manual says to leave the clutch lever engaged (raised position) no longer than 15 minutes at a time.
I've got a Zetor 8441. I have to lift slightly on the PTO clutch handle in order to start it. The owner's manual refers to it as a safety switch. If I forget to lift the handle, it acts exactly as you describe.
Greg
We"ve got an early eighties model 580C. The seal on the top of the steering valve started leaking and it pumped oil up through the steering column. We replaced the seal with an OEM Case part and did nothing else to the valve. After reinstalling the valve, the wheels pull all of the way to the...