OK, here is the situation:

My water shuts off for no rhymn or reason. I go outside to the pit where my tank and switch are located, reach down inside the pit (approx. 5' deep) and tap the switch cover with a broom handle. The water comes back on. I may have water again for for two days or two hours before this happens again.

Some things that may be noteworthy:
The pressure gauge on the tank seems to always be at 40 psi, whether I have water or not.
When the water comes back on I usually get air out of each of the faucets in the house.
The switch itself looks good, at least to my un-educated eyes. I removed the switch cover and the wires were all tight and there was no sign of corrosion anywhere.

The switch has two spring-like looking adjustments. I assume these are hi and low? Is it possible one or both of these need adjusted? And if so, how do I go about this?

Please forgive my ignorance. Any suggestion would be greatly appreciated.