Regarding rewind, sorry, I spaced out and searched for 5hps (tho Gale had the habit of making both “Standard” and “Deluxe” models, thru the years. In the 50’s they could be significantly different (different powerhead)).
Here’s a FB post with a 1947 Hiawatha 3hp (at a Museum in Galesburg!), which looks very much like yours:
http://www.omc-boats.org
http://www.aerocraft-boats.org