Imho the power head
is not from a 1941
Mercury KB-3
it May have been
Replaced with a
1940 Sea King or 1941
Sea King power head
and popet valve
style carb! The 1941
Mercury was a deluxe
model that did not use
a popet valve style
carb. The popet style
carb would not work
or fit under the lower
carb cover.
You could very well be correct about my poppet valve carbed powerhead
being a cousin to a Mercury, but the only reason I question this,
is the Tillotson Carb data, showing the KB3 had the AJ carbs,
but not until 1946.
Prepare to be boarded!