Thermostatic Air Cleaner: Service and Repair

Fig. 20 Removing vacuum diaphragm (Typical):

VACUUM DIAPHRAGM, REPLACE
Carbureted Engines
1. Remove air cleaner housing.
2. Disconnect vacuum hose from diaphragm, drill through welded tab, Fig. 22, and tip diaphragm forward to disengage lock, then rotate diaphragm counterclockwise. When diaphragm is free from snorkel, slide complete assembly to one side and disengage operating rod from heat control door.
3. With diaphragm removed, check door for freedom of travel. The door should fall freely when released from the full up position. If it does not, check door to snorkel side walls and hinge pin for interference.
4. Remove any foreign matter with compressed air.
5. Reverse procedure to install. Pop rivet tab into place and connect a hand operated vacuum pump to diaphragm. Apply 9 inches Hg vacuum to diaphragm hose nipple and check that control door operates freely. Manually operating the heat control door could result in damage, leading to malfunctioning of the system.

Fig. 21 Replacing heated air inlet temperature sensor (Typical). Except 4-153 engine:

Fig. 22 Replacing heated air inlet temperature sensor. 4-153 engine:

SENSOR, REPLACE
1. Remove air cleaner housing.
2. Disconnect vacuum hoses from sensor, then remove retaining clips and the sensor.Figs. 21 and 22.
3. Reverse procedure to install, using a new gasket and retaining clips. Do not attempt to adjust the sensor.