I used to have a 1960 Johnson super sea horse 40 hp if I remember right the oil mix was like a quart to 6 gallons of gas. It woulf turn water in a trash can pretty quick. I found everything on the motor and still have it somewhere, found it all on ebay and local shops. Only thing I couldn't find was rings for the pistons. It was the only motor ever made that had a water choke on it. Got some funny looks in the marine store when I asked about that. Mechanic in the store said he worked on motors for 25 years and never heard of it. Owner was asked and he identified the motor by mechanic saying it had a water choke. I bought mine to go on a old 1956 Chris Craft. Wooden boats are great where you live, but not in the south, too much upkeep. Sounds like a nice boat and a lot of fun to own. The steering is probably a cable steer with pulley's so that could account for the vibration.