Continental Motors GTSIO-520 SERIES Operator's Manual page 43

pressure reading was low, the oil pressure relief valve may be
malfunctioning because of dirt. Remove the valve and clean and
inspect parts. Inspect seat and plunger face for nicks and scratches
and other defects which would affect operation. After reinstalling
valve, adjust oil pressure to the 30-60 psi desired range by turning the
adjusting screw. Turn screw clockwise to increase pressure and
counterclockwise to decrease pressure. Secure adjusting screw with
locknut when adjustment has been completed.
j. The spring-loaded oil temperature control valve may
malfunction if it becomes contaminated with dirt or foreign
particles. Remove the valve and clean in fresh solvent. Inspect seat
for possible damage. No repairs or adjustment can be made to the
unit. If thermal action is questionable, the travel of the valve may be
checked by immersing the assembly in heated water. Valves marked
173°F. should travel a minimum of 0.16 inch as the water
temperature is raised from 135°F. to 173°F. Valves marked 77C
must travel a minimum of 0.09 inch between120°F. and 170°F.
Replace the valves which do not pass this test.
k. The idle mixture adjustment is the locknut at the metering
valve end of the linkage between the metering valve and air throttle
levers. For the LEFT HAND ENGINE, tightening the nut to shorten
the linkage provides a leaner mixture. A richer mixture is obtained
by backing off the nut to lengthen the linkage. For the RIGHT
HAND ENGINE, tightening the nut provides a richer mixture and
backing off the nut provides a leaner mixture. Adjust to obtain a
slight and momentary gain in idle speed as the mixture control is
slowly moved toward idle cut-off. (If set too lean , idle speed will
drop under the same conditions.) (See Figure 8)
The idle speed is controlled by a spring-loaded screw located
in the air throttle lever. Set to values specified in aircraft handbook
by turning in to increase and out to decrease idle speed.
Current fuel pumps may be adjusted for both idle and full
throttle fuel pressure in accordance with Service Bulletin M72-4.
1.
Check starter and generator/alternator for security of
attaching parts and electrical connections. Check for oil leaks which
are indicative of a defective oil seal.
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