The fuel mix is 24:1
I just recently purchased a 1957 Evinrude Fleetwin in Burlington Ontario for 200.00 It needs tuning but is in good condition
A 1957 Evinrude 18 hp weighs 85 pounds, so I would assume the Johnson 18 hp would be about the same, give or take a few pounds.
50 pounds
I would guess that this engine in mint condition would be worth at least $500.
1957
A Johnson outboard engine, model number RDE19M, would be a 1957 year model, 35 hp outboard.
50 to 1 oil to gas
It is a 1957
1957 5 hp 4000 rpm
24:1 fuel / oil mix. OMC didn't go to 50:1 until around 1962/63. That outboard was equipped with the 2 line pressure tank system. I would update with a fuel pump that they put on some 1958 and all 1959 models so you can run it off any fuel tank if it hasn't already been done.
JW-13 motors are all made in 1957
The year for the 15020 model of the Evinrude Fastwin is 1957 and it has 18 horsepower. The 15541 is a part number for the model of the motor; it is the e-force universal carbureted supercharger kit.