Re: Old evinrude sportsman, need info.
I'm working on a '47 4416 myself. I found that the years of gunk in the gas tank was removed in just hours with the help of a "paint and varnish remover". It cleaned the interior of the tank right down to the shiny aluminum. Just throw a cup or two in and slosh it around every 30 min. I would not use it on the carb, but it did a great job on the tank.
You had mentioned that you changed the plug in yours. I need to do the same with mine, but I do not know the correct plug# or gap. Do you have any information on the recent plug to use on a '47 sportsman 2HP 4416?
Thanks, Ken