If you're getting drips that fast while at rest, then spinning should yield much higher rate. Are you sure that your just not flinging the drops all over the engine compartment?
Do this experiment:
Adjust the drip rate to the few drips a minute when not spinning the shaft. Make sure that you do this with the locking nut tight. Go for a ride with the motor running while having someone else drive. Go below and put a piece of Cardboard round the stuffing box, but about 5 or so inches away. See if the cardboard gets wet, if it does, then you're just flinging the water off instead of dripping, which is why you don't see it drip. Also, is the front of the packing nut wet, by front I mean where the shaft enters the nut from the motor side. If so, the water is getting to the shaft and cooling
When locking the locking nut, it is very easy to think that you are not moving the nut, when in reality your moving it also.
Thanks for the thoughts but thats the problem...I can't get stuffing box to drip at all with the locking nut tight! For instance I tried backing off the packing nut so that it was just about off and water was pretty much gushing in. As soon as I tightened the locking nut - no drips at all and regardless if the packing nut was moved slightly while tightening it, it was way too loose anyway so it wouldn't have mattered.
Also I do know what you mean about the spray but today my girlfriend was at the helm and I had my had in the engine compartment the whole way with my hand on the stuffing box and I am 100% positive there was no drips or spray for that matter. Its the weirdest thing I can adjust the packing but so that water is either gushing in or I get the perfect few drops a minute but in either position as soon as I tighten the locking nut - no water/drips/spray period.