Seems like there are always threads about Ns with the clutch disengaging erratically, if at all. Several things cause this; lack of regular use, gummy oil on the clutch plate from a leaking seal in transmission, moisture leading to rust. The correct solution is to split the tractor and repair/replace the issues. Participants on this site often look for shortcuts to avoid the work and expense involved in the full repair...block the pedal down, drag the brakes, drive tractor into a tree, etc. I've found a shortcut fix that works better than all others.
Brake cleaner sprayed on the clutch plate and flywheel will cause the clutch to function properly without sticking. First, the clutch must be disengaged. Heat is the best aid I've found. In lieu of a hot summer day, I direct the heat from my salamander jobsite heater at the bell housing with the clutch pedal blocked down. If the clutch doesn't spontaneously release I may need to start the tractor in gear and drag the brakes.
I drill a 7/32" hole into the bell housing on the right side about 2" back from the parting line at about the 2:00 O'clock position. Using the little tube supplied with the brake cleaner can I spray fluid into the compartment in the direction of the back of the flywheel. With the brakes locked on I do this with the engine running and the clutch pedal depressed, then ride the clutch for a couple of seconds. This creates heat and friction on the clutch disk and aids the clutch cleaner to work the guck out of the clutch disk. Be sure the drip hole in the bottom of the housing is open because alot of nasty stuff runs out. I repeat this time and again until I've used the entire can of cleaner. When finished I tap my 7/32 hole to 1/4"x20 and close the hole with a stubby machine screw.
This method has worked every time I've used it.
Best regards, tOTG