Re: 1972 Johnson 4 hp vs. 1966 Evinrude 3 hp best option same price
I believe that by 1966 they were moulding a boss into the cylinder block on those to accommodate an auxiliary fuel pump. If you take the lower cowling off, there should be a hole with a screw in it with two smaller holes on either side of it. The screw is a plug that you would remove to mount the fuel pump. A new fuel pump can be had at a dealership and you can get the standard Johnrude male fuel fitting there, too. I believe you'd also need a 2-way fuel valve from the tank so that the fuel pump can run independently of the gravity feed, too... Or you could just plug off the gravity feed and run the auxiliary tank exclusively...