Throttle control handle will not stay at one location on the quadrant on my 1944 2N. It will not stay in place unless I hold it there, even just idling, much less when I’m actually moving and using the tractor. Slips back toward the top (the idle end) of the quadrant. Also seems to have very little functionality at the idle end of the quadrant (does not seem to do anything until it is one-half to three-quarters down the quadrant toward the wide open (bottom) end. Once tractor is running and has warmed up just a little, I can actually push the throttle handle slightly past the bottom of the quadrant where it will lock in and stay there and then run wide open. What do I have going on here and what is the fix? Many thanks in advance for any helpful replies.