I have a Teel pump that I use to pump water from a river to water my garden. This year for the first time it does not shut off when I stop using the water. I took the top of the Pumptrol control unit off and with a screw driver, lifted the tab (magnetic I think) and the unit shut off. I'm assuming that I need to adjust the larger of the two screws to adjust the pressuer, but I do not know which way to turn it - increase or decrease pressure. I really do not want to screw things up so I'd appreciate an answer.

Sometimes those contacts on the pressure switch get kind of welded together. Which kind of sounds like what may have happened, sense no known changes in the settings on the switch. I would try cycling the water again and see if it shuts off as it is supposed to without having to pry the switch open. I doubt that with no pressure on it that it was the setting on the pressure switch. FYI, a lot of times the instructions for the pressure switch are on the inside of the cover you took off. If it stuck once, it could stick again. Get back to us. Thank you1

This year for the first time it does not shut off when I stop using the water.

When you stop using the water (turn off a valve?), the pressure would likely spike. If the switch is not turning it off, you could try turning the large center nut counter clockwise. That will lower the pressure at which the pump will cut off. You might want to take an emory board and take a few strokes on the points with the power, of course, turned off.