Section XV. Air Shutdown Housing and Blower
Air Shutdown Housing. Air shutdown housing is mounted on right side of engine on blower, and serves as a
mounting for air cleaner. Air shutdown housing contains an air shutdown valve that shuts off air supply and stops engine
whenever abnormal operating conditions require an emergency shutdown.
Blower assembly, mounted on right rear side of engine block, supplies fresh air required for combustion
and scavenging. Two hollow double-lobe rotors revolve in rotor housing. Revolving motion of rotors provides a
continuous and uniform displacement of air.
Gears located at splined ends of rotor shafts assist in spacing rotor lobes. Normal gear wear will have
some effect on rotor-to-rotor clearance. A combination of gear and rotor shaft bearing surface wear will result in a
decrease of rotor to housing clearance.
Oil seals, consisting of a fiber washer, O-ring, retainer and seal spring are Incorporated in each end of the
5-58 Blower Inspection (blower Installed)
When Inspecting blower on an engine with engine running, keep fingers and clothing away from
moving parts of blower and run engine at low speed only. Equipment damage and severe
personal injury can occur if clothing or fingers enter moving rotors.
Blower, with a removable air inlet housing can be inspected without being removed from engine, (Fig. 5-25).
Remove air shutdown housing and screen and inspect the blower as follows:
Inspect rotors for scratches, chips or other abrasions. If burrs cause interference between rotors or
between rotors and housing blower must be removed and repaired or replaced.
Start engine and check for leaking oil seals. Leaky oil seals are indicated by presence of oil on blower
rotors or inside the surfaces of housing. Run the engine at low speed and direct a light Into the rotor compartment at end
plates and oil seals. A thin film of oil radiating away from seal Indicates an oil leak is present.