I have a john deere 300, the pto unit was working just fine and it just suddenly quit, I checked wires and everything appears to be connected, the engine runs but the pto just won't engage there are no repair shops close to me at all any thing I can took at and try>

There will be a inline fuse for the pto circuit check that.
Some of the old ones you had to adjust air gap pn the clutch , the ones built in the late 70tys and 80tys.
The new 300 has no adjustment.
Luck

We will check it out never thought of that, was my father in laws tractor and I would like to keep it going. Thank you very much have not used this site before but if we can I will let you know if that was the problem thanks again