The pendulum is what is running the clock and keeping accurate time. The pendulum bob can be adjusted up or down to adjust the time to run faster or slower.

Remove the pendulum and move the pendulum disk down on the pendulum stick if the clock is fast. Push the disk up if the clock is slow. 1/16 inch will change the clock about 2 minutes per day. Be sure to set the correct time after each regulation. You may need to continue to make adjustments a couple times in order to get the time perfect.