TM 10-3950-672-24-2
Section 5. Air System
Subject
Page
Air System Flow ......................................................................................................................................
Diagnosing Air System Malfunctions .......................................................................................................
Air Flow Restriction Results in Excess Smoke and Low Power ...........................................................
Damage from Non-Filtered Air ............................................................................................................
Air System Replacement Procedures ......................................................................................................
Intake Manifold Cover and Gasket ......................................................................................................
Exhaust Manifold and/or Gasket .........................................................................................................
Exhaust Manifold Inspection ...............................................................................................................
Intake Air Restriction ..........................................................................................................................
Air System
Air System Flow
Air is pulled into the engine from an air filter. Clean air is very important to the life of the engine. Ingested dust and dirt
can damage the cylinders very quickly.
Caution: Make sure that a quality air cleaner is used and that it is periodically replaced according to the
manufacturer's recommendations.
Intake air for naturally aspirated engines flows directly from the filter to the intake manifold. From the intake manifold, air
is pulled into the cylinder and used for combustion. After combustion it is forced out of the cylinders through the exhaust
manifold.
Intake Air, Exhaust and 4B3.9
Fuel System
Intake Restriction at
Rated Speed and Load
with Dirty Air Filter
Element - mm H20 [in.
H20].....................
508 [20]
Exhaust Restriction at
Rated Speed and Load
- mm Hg [in. Hg]......... 76.2 [3 in.]
Diagnosing Air System Malfunctions
Air Flow Restriction Results in Excess Smoke and
Low Power
from the intake air. Restricted air flow changes the air
to-fuel ratio, reducing power and increasing smoke from
the engine.
Verify that the air cleaner is being
maintained correctly.
NOTE
Air restriction is indicated by an air
restriction indicator mounted in the
air intake tubing on the output side
of the air cleaner assembly.
5-111