getting the manual is a half assed answer.

Might want to reply with everything in this group with that crap.

Anyway....
Is this screw located under the powerhead???

There are normally two screws by the skeg.
One on top and one on the bottom.

Thinking about it a bit more, when was the last time
you changed the water pump impeller on the motor?
You might as well drop it and then change it yourself.
Put back everything nicely and you've just done some
seasonal maintence.