An Emergency Frequency (Cycle) Meter Check
When the Frequency Meter on your gen-set goes out, or is in question, try this: Check the accuracy of the frequency meter with a 120-volt clock (with a second hand), and a good wristwatch.
1-Just plug the 120-volt clock into the circuit powered by the generator and coordinate its second hand with the seconds on your wrist-watch.
2-Next, watch for three minutes to see if the generator-powered second hand runs faster or slower than the second hand on your wrist-watch.
3-Adjust the generator engine-speed until the second hand of the 120-volt clock matches the one on your wrist-watch.
(Some of this material excerpted from PRACTICAL BOAT MECHANICS, Ben L. Evridge, to be published this fall)