"The 1964 18hp Evinrude/Johnso
"The 1964 18hp Evinrude/Johnson inorporates all needle, roller, and/or ball bearings within all of the powerhead moving parts without exception.
As such, it is quite safe and has been recommended by OMC to use the 50/1 mixture (1pt 50/1 oil to 6gal gas). A octane rating of 87 will be fine.
The above recommended mixture really shouldn't smoke as you've indicated. I suspect that perhaps the carburetor is misadjusted or you have excess oil left over from another period, or the gas itself may be old.
(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)
Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.
Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.
Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.
Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.
When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway."
