5-79. APU GOVERNOR - Continued
Adjust engine speed (rpm) by turning engine speed adjustment nut. Use screw driver to prevent
stud from turning and turn nut clockwise to increase speed, counterclockwise to decrease speed.
Sensitivity (no load to full load speed drop) is adjusted by turning the sensitivity adjusting ratchet
nut accessible through hole in side of blower housing. 'If speed drops too much when full load is
applied, turn the ratchet nut counterclockwise to increase spring tension and compensate for
reduced rpm. An over-sensitive adjustment, approaching no speed drop when load is applied may
result in a hunting condition (alternate increase and decrease in speed). Adjust for maximum
sensitivity without hunting. The use of a reed-type frequency meter will give the most accurate
results. A mechanical tachometer can be used on the generator thru stud, but this is not generally
as accurate. It should be possible to adjust for a sensitivity of less than 3 cps, and 2 cps is usually
After adjusting speed and sensitivity, secure speed stud lock nut and replace dot button in blower
Install gear cover (see para 5-68).
Install APU (see para 4-207).