Hi
That is a Badge motor built for Gambles by Muncie Model# 10D2 1940 Neptune 2hp single The D in the serial number and the rubbed out or missing name brand on the rope plate is the key for proper ID. Near as we can tell Gambles contract only lasted two years. Jug was painted gold,Tank had a chevy orange color, Block and steel transom/parts dull aluminum, polished lower,brass stem and exhaust tube. The rest of the small parts were nickle plated.
You have a very nice complete unmolested example for this unit. All the Models for this year were offered from gambles built by Muncie. If any of you guys happen to come across a nice example for the Gambles 6hp Alternate twin,9hp alternate or the master 16 decal We would like to have pictures to add to our Neptune files.
Best regards
Brian