Engine Service Manual

64
Emission Compliant Systems
KohlerEngines.com 32 690 03 Rev. I
SECONDARY EMISSION COMPLIANT SYSTEM
Twin Secondary Air Induction System
A
Hose To Exhaust
Manifold
B Inlet Screen C
Secondary Air
Valve Assembly
D Hose To Carburetor
E
Hose To Exhaust
Manifold
Single Secondary Air Induction System
F
Secondary Air
Valve Assembly
G
Hose To Exhaust
Manifold
H Hose To Carburetor I Inlet Screen
A
B
C
D
C
E
F
G
F
H
I
Operation
Intake pulse of engine activates secondary air valve.
Air is drawn through an inlet screen of secondary air
valve. Air is then drawn into exhaust manifold and
muffl er where it mixes with any unburned hydrocarbons,
which then burn in heat of muffl er. A hose is connected
between a carburetor port and a diaphragm chamber
in secondary air valve. Carburetor vacuum moves
diaphragm to close valve when air induction is not
required, primary idle.
Maintenance
Air inlet screen in secondary air valve can be removed,
cleaned, and reinstalled. If inspection of system reveals
any damage or decomposition of hoses, secondary air
valve, or exhaust system, parts should be replaced.
For engine to be Tier III compliant, it may be fi tted with a secondary air induction system (SAI).