Trouble Shooting; Oil Temperature Gage; Fuel Quantity Indicating System; Removal And Installation - Cessna 150 Series Service Manual

15-37. OIL TEMPERATURE GAGE. 15-41. REMOVAL AND INSTALLATION OF FUEL
15-38. DESCRIPTION. The oil temperature gage is a. Drain fuel from tank. (Observe precautions in
an electrically operated indicator mounted in the Section 12).
instrument cluster with the oil pressure gage. One b. Remove access plate above fuel tank for access to
electrical lead is routed from the indicator to the
transmitter.
sending unit, installed in the engine. The other lead c. Disconnect electrical lead and ground strap from
supplies power from the bus bar to the indicator. Refer transmitter.
to Table 1 on page 15-16A when trouble shooting oil d. Remove screws attaching transmitter and
temperature gage.
carefully work transmitter from tank. DO NOT
BEND FLOAT ARM.
15-39. FUEL QUANTITY INDICATING SYSTEM. e. Install transmitter by reversing preceding steps,
using new gaskets around opening in fuel tank and
15-40. DESCRIPTION. The magnetic type fuel quan- under screw heads.
tity indicators are used in conjunction with a float- f. Service fuel tanks. Check for leaks and correct
operated variable-resistance transmitter in each fuel quantity indication.
tank. The full position of float produces a minimum
resistance through the transmitter, permitting NOTE
maximum current flow through the fuel quantity
indicator and maximum pointer deflection. As fuel Ensure transmitter is properly grounded in
level is lowered, resistance in transmitter is increased, accordance with Section 12.
producing a decreased current flow through fuel
quantity indicator and a smaller pointer deflection.
15-42. TROUBLE SHOOTING.
TROUBLE
PROBABLE CAUSE REMEDY
FAILURE TO INDICATE.
No power to indicator or trans-
Check fuse and inspect for open
mitter. (Pointer stays below E.)
circuit. Replace fuse, repair
or replace defective wire.
Grounded wire. (Pointer stays Check for partial ground between
above F.)
transmitter and gage. Repair or
replace defective wire.
Low voltage.
Check voltage at indicator.
Correct voltage.
Defective indicator.
Substitute known-good indicator.
Replace indicator.
OFF CALIBRATION.
Defective indicator.
Substitute known-good indicator.
Replace indicator.
Defective transmitter. Substitute known-good transmitter.
Recalibrate or replace.
Low or high voltage.
Check voltage at indicator.
Correct voltage.
STICKY OR SLUGGISH
Defective indicator.
Substitute known-good indicator.
INDICATOR OPERATION.
Replace indicator.
Low voltage.
Check voltage at indicator.
Correct voltag
Change 1
15-15