Marvel mystery oil with 20% Stp. This is what I learned from Ed Fisher 30 years ago. Works great, jus stir it up good and get one of those old fashioned brass Oiler cans.
I have several tether boats I built and ran in the late ‘50’s and 60’s in Seattle and also a collection of props we ran. The boats are not real pretty and I want to restore them some day. I don’t know how to post pictures but will try to figure it out.
Tetherguy