Depends, is the York under driven?
If your using the OBA.com pully I believe you to be using, Works fine at stock idle if you simple airing up tires, if you want a little more umph, and cause my thumb throttle is sitting in my living room, I simply rev the motor a little at the throttle body.
I think you mounted yours on it's side, you want to be care ful of over revving cause you'll discharge all the oil and say good buy york!! I would venture to guess to keep it under 1500 rpm's