I agree with the others, leave it on all the time. If you're worried about working it at WOT when backing up and now throwing snow, you could back the throttle off a bit but leave the PTO engaged or remember that these motors were designed to be run at 3600rpm so don't be afraid of hurting it. If there was no load on the motor then it's usually not a good idea to run WOT but with the thrower on, you're ok in that regard.
