Propeller Owner’s Manual
139
TESTING AND TROUBLESHOOTING
61-00-39
Page 4-4
Rev. 17 Apr/20
2. Troubleshooting
CAUTION:
INSTRUCTIONS AND PROCEDURES IN
THIS SECTION MAY INVOLVE PROPELLER
CRITICAL PARTS. REFER TO THE
INTRODUCTION CHAPTER OF THIS
MANUAL FOR INFORMATION ABOUT
PROPELLER CRITICAL PARTS. REFER TO
THE ILLUSTRATED PARTS LIST CHAPTER
OF THE APPLICABLE OVERHAUL MANUAL(S)
FOR THE IDENTIFICATION OF SPECIFIC
PROPELLER CRITICAL PARTS.
A. Hunting and Surging
(Rev. 1)
(1) General
(a) Hunting is characterized by a cyclic variation in
engine speed above and below desired speed.
Surging is characterized by a large increase/
decrease in engine speed, followed by a return to
set speed after one or two occurrences.
(b)
If propeller is hunting, a certified airframe and
powerplant mechanic with the appropriate rating or a
certified
propeller repair station with the appropriate
rating should check:
1 Governor
2 Fuel control
3 Synchrophaser or synchronizer
(2) If propeller is surging:
(a) Perform the "Initial Run-up" in accordance with the
Inspection and Check chapter of this manual to
release trapped air from the propeller.
1 If surging reoccurs it is most likely due to a faulty
governor.
a
Have the governor tested by a certified
propeller repair station with the appropriate
rating.
