It has been a long while since I have had to rent motors, that was in my youth, I grew up around Edmonds.
BUT, we used to rent em at any rental place, and McConnels boathouse, back then.Aurora Rents comes to mind, they rent boats too.
Now I have a boat and a kicker that seem to work good, so I don't rent em anymore.

I would try any rental place, they usually have motors for rental. If not email me, go for a ride and pitch in for some gas/launch fees!

I always launch at Edmonds, I like to be "centrally located.

Hope that helps
WW