KB-1A was the Standard model,,, no frills
KB-3 was the Deluxe model rewind, cowl, spark plug cover and the rubber wedge between tank and spark plug cover,
Early in 1941 production there was a KB-1 single with poppet valve, KB-1A had carburetor with cam on magneto plate linking spark advance to throttle opening. KB-1, KB-1A were intended to have the PreWar pattern cast aluminum fuel tanks. By mid summer 1941, restrictions on use of aluminum led to KB-1 model being dropped and KB-A to change to a new pattern stamped steel fuel tank,
KB-2 Streamline model has steel sheet metal cowling is uncommon and even more so if all the sheet metal is present.
Your KB-3 has the correct 4 stud fuel tanl and has the hex mounting studs SO I believe it had the extras when it left the factory. A possible explanation for the RED paint is to make it stand our…LOTS outboards were stolen and Mercury provided stolen motors lists to its dealers in hopes that all motors brought in for service would have its serial numbers would be checked, It is not uncommon to see a deep scratch on an ID plate obscuring the serial numbers. Boat livery might also give their outboards a stand out color to keep the customer honest. It appears that front mounting studs have non original spacers or fasteners. The standard of workmanship outside factory varied…missing, butchered or wrong fasteners indicate low level of skill by mechanic .
What would I do with your KB-1A and KB-3? My usual method is to tear down, clean, evaluate condition of parts, prime, paint and assemble what you have and keep looking for cown, spark plug cover and the rubber wedge. Correct fasteners may not be available, but, there is not much easier than replacing fasteners. I do things this way, because there is not much more depressing that a grungy down on its luck Little Merc. Likewise, a freshly painted and assembled Little Merc is a very compelling reason to find the parts and finish the job. About 80% of job is tear down and cleaning, prime and paint. The rest is FUN. Louis
