Re: 1957 evenrude 3 hp won’t run

[Don]

Well, it would seem as though you haven’t cleaned the carb thoroughly. The 57 models had adjustable needle valves, not fixed jets. The needles shouldn’t need to be replaced unless physically damaged. Was the inside of the carb dirty/gummy when you pulled it apart? I would look for problems/gum/varnish in the main nozzle well, along with the high speed needle passage in the carb bowl…
Marineengine.com should have carb kits in stock, and most local Evinrude dealers might have it is stock as well
PS- where did you have the needle valves set for initial start up?
The high speed needle/bottom one should be set 3/4 turns out from gently seated
The low speed needle/top one should be set 1.5 turns out from gently seated