On the one I had, the pump was remote mounted. I'm sure yours isn't like that, you'd have to disconnect the hoses to remove the engine.
Follow the wires from the pump to their location in cowl.
If you are comfortable with disconnecting those two, do so.
With a battery booster, clamp one wire with the alligator clip, touch the other wire to the other alligator clip. If the pump runs and the motor goes the wrong way, reverse the wires.
And be careful, even on a real good engine stand outboards are dangerous to maneuver. Think about getting one of their engine hoists also, cheaper than a hospital trip or having to find other engine parts if it gets away from you while repositioning.
Also, If you don't have one of these, get one.
http://www.mbsmfg.com/mercury-marine...ting-ring.html