Salnaes, I actually use synthetic oil. I started in the late 1970’s using Amsoil. Sometime in the 90’s I began using the Pennzoil, Full Synthetic as it was biodegradable. When they discontinued it I bought all I could. There was almost no smoke and any oil slick on the water would disappear. I pretty much ran out in 2022. Finding a full synthetic, biodegradable, replacement has been challenge. The “G” oil is no longer being manufactured. I can find the BelRay on eBay but the BelRay website no longer list a biodegradable oil. Last year I bought a gallon of the Stihl HP ultra biodegradable oil and was comparing the Belay biodegradable oil to the Stihl HP, running two 1929 Elto Folding Lightweight’s. I believe I was using the BelRay when running them separately, and the Stihl HP when running them together. I’ll add a video link below. In most all my outboard motors I run 3 oz. per. gall. A bit more that 2%, but as we use ounces and gallons here, it keeps it simple. Most of my motors are pre. WW-II bushing motors, however I do have a few from the 50’s and 60’s. I just bought more BelRay and another gallon of the Stihl HP to do more comparing on a 1931 Johnson OA-55 this year. I have recently learned how to do videos and have some in a play list on my you tube site. All except the small1 hp. motors are running run on that mix, and all but the twin 1929’s are running on the Pennzoil. What synthetic oil are you using? This is not a recommendation – just my experience. You might find it interesting that this Johnson service bulletin updated the oil ratio to 50 to 1 for your motor over 50 years ago.
Video link https://youtu.be/l1ext_nsrYM?si=wphqpdoI6Mqq-P0t.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.