Jd it looks like you have already cover this but my Cub was doing that and it ended up to be nothing more than a low battery. Those electric clutches pull a load that can do that without a good battery.
mark, just went out and tried a new truck battery with 1150- ca and it did the same thing, i cant find the circut breaket in the wiring, supposed to be one between pto and ammeter??? i have a wiring illustration, thnx cy