Farmer fixes

[Cool Hand Lurker]

This brings out a lot of questions, like:

Is a "rough service" bulb necessary?
Do you need a carburetor fuse?
If the bulb burns out will it cut off the gas flow?
If the bulb is too big should you add a resistor?
Does the bulb make the gas lighter for better combustion?
With a round bulb, how do you know which side should be up?
Would an LED work just as well?