Mark, I would start by using 120 grit on a pad sander. You can leave some of the original paint as it was very strong. I use bondo on any dents or badly scratched areas . Then 320, followed by a few coats of self etching primer, after I use a light grey filler primer, and then color coats. Make sure you use a light color grey filler primer, or your topcoat colors may look muddy and dull.
That’s motor is a bit tricky to paint as it had two different colors. Look around on the internet for pictures of an original 55 motor for paint and decal placement. I would shoot the white portion first, then mask the white and shoot the blue. That way the white goes over the lt grey primer, and not the blue. It will make the white pop. I’m not a fan of clear coat as most of the motors I have seen clear coated seem too shiny and over restored. Some members have mentioned using a semi gloss clear, but I have not tried it.
Retro Paints has good color matched paints . In order to mask with sharp lines use 3M 06404 fine line tape. Make sure you get the correct vinyl decals after all of your hard work.
I use basically the same methods on all of the motors that I restore. Hopefully other members have some additional tips / techniques. Just remember the painting is the easy part, it’s the many hours of sanding etc. that will give you fantastic results.
Here is a picture of a 1958 Johnson 10HP that I restored using the above method.
Hope this helps,
Bob D
