Got my chance to use the finish mower for the first time today and did so without an overrunning clutch (contrary to all of the advice). I mainly skipped it because I will have to cut down the PTO shaft to fit it between the tractor and mower, so I thought I give it a try in the open to see what would happen....
....nothin'.
I didn't get any push or anything. As soon as I pressed the clutch, the PTO rapidly lost speed and stopped with 3 or 4 seconds, maybe less. During that time, the tractor just sat still (I tried it several times on purposed while in the open part of the yard before actual beginning to mow). I decided to mow without and had no problems.
I definately agree with Reed, though...the installation of the clutch will make shifting gears easier. I will probably break down and cut off the PTO shaft soon and put the clutch on (I've got one of the clip-on models from Agri-Supply, so it's no big deal).
Thanks for the input and help.
P.S. - How on earth did I get by all these years without a finish mower? I usually push mow for about 2 1/2 hours, now I'm down to an hour of finish mowing and 1/2 hour of pushing (for trimming purposes).