Why not add a small electric trolling motor?

Norm Dion wrote:

I currently have a Yamaha 2.5 HP 4-stroke outboard with a 7 1/4 X 6 aluminum
prop.

The type of fishing I do ( lake trolling ) requires a very slow speed but
this particular setup, even at the
very lowest idle, provides too much forward speed for the lures I like to
use.

I'm assuming there are few options other than replacing the prop. Am I
correct, or am I missing something?
If a different prop is the answer, what would be the proper one to get me a
slower speed? What would it's specs
be, and would it fit the Yamaha hub? I'd even like to boost the RPM's up a
bit from the low-idle position.

TIA