David. Hobby`s do one, which is unfortunately 127mm tall…and likely the one you are talking about. Apart from that i have not seen any model outboards, and unless you have a lucky “toy” find I think that you may have to make your own.
I had the same trouble for the TOYBOATA and made one up from balsa. It is no great feat of modelmaking but there is not much detail on an outboard. Mine is a dummy, and acts as a rudder, the prop being just in front, and it looks very effective in the water.