Kohler CH18-CH26 Service Manual page 64

Section 5A
LPG Fuel Systems
High Altitude Operation
The standard carburetor calibrations will provide
proper operation up to altitudes of 1500 m (5000 ft.).
No internal changes are necessary or available for
either carburetor.
NOTE: Carburetor adjustments should be made only
after the engine has warmed up.
Idle Speed Adjustment
1. Start the engine and run at half throttle for 5 to 10
minutes. Check that the throttle and choke (Nikki
carburetor) plates can open fully.
2. Place the throttle control into the "idle" or
"slow" position. Turn the low idle speed
adjusting screw (See Figure 5A-2 or 5A-3) in or
out, to obtain a low idle speed of 1200 RPM (± 75
RPM), or set to application specifications. Check
the speed using a tachometer.
NOTE: The actual low idle speed (RPM) depends on
the application. Refer to the equipment
manufacturer's recommendations. The low
idle speed for basic engines is 1200 RPM.
LPG Fuel System Component Service
LPG Carburetor - Cleaning
The carburetor may be cleaned if necessary. Removal
from the engine and limited disassembly will aid in
cleaning.
NOTE: Impco Carburetor: Do not loosen or alter the
mounted position of the clamping brackets
and/or stop collar on the throttle shaft. Each
is preset, in correlation to a specific position
of the throttle plate (shaft), or acts as a stop.
None of these attached components,
including the throttle plate or shaft, requires
disassembly or removal for any carburetor
servicing. All the components on the throttle
shaft should be left intact. If the settings of
any one of these is inadvertently loosened or
altered, each must be checked/reset, or
performance and operation will be affected.
Refer to the procedure included in the
reassembly/installation sequence to check or
reset.
5A.4
Impco Carburetor
1. Turn off fuel supply at tank.
2. Remove the air cleaner, breather hose, fuel line,
vacuum hose, choke, and throttle linkages.
Remove the mounting hardware, carburetor, and
gaskets from the engine. Discard the gaskets.
3. The carburetor venturi may be removed for
inspection and appropriate cleaning.
a. Remove the four screws securing the air
cleaner adapter and gasket to the carburetor.
See Figure 5A-4.
Figure 5A-4.
b. Important: Mark a small line on the outer
edge of the venturi for proper orientation and
reinstallation later.
c. Loosen the venturi retaining screw on the side
of the carburetor body and lift out the
venturi. See Figure 5A-5.
Figure 5A-5.