What you’re missing is the spring and pointed slug
that keeps it in position.
Your MS4B carb is probably unusable if you want
to run it. You’ll find that the metal has become
soft and brittle. Tighten anything threaded and the
threads strip. The carb was used on several later
motors and the issue with the pot metal was resolved
somewhat but caution should still be used when tightening
anything on the later ones as well. I believe any MS45
is the same but the MS45-A & MS45-B are the easiest to
find because it was used on so many Neptune’s BUT
you don’t want an early A as it will have the same issue.
The only difference will be the fitting for the fuel line.
The Neptune’s are plentiful and not in high demand.
Often you can buy the whole motor for less than someone
will ask for just the carb. If your carb is still in one piece
its nice to keep with the motor as many have turned to
dust. Its the prop nut that I’m curious about.
Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.