Kohler command pro CH940 Service Manual page 33

NOTE: Engines will have fixed low idle or limiter caps
on idle fuel adjusting needles. Step 2 can only
be performed within limits allowed by cap. Do
not attempt to remove limiter caps.
1. Place throttle control into idle or slow position. Adjust
low idle speed to 1200 RPM. Follow Low Idle Speed
(RPM) Adjustment.
2. Low idle fuel needle(s) setting: place throttle into idle
or slow position.
a. Turn 1 low idle fuel adjusting needle out
(counterclockwise) from preliminary setting until
engine speed decreases (rich). Note position of
needle. Now turn adjusting needle in (clockwise).
Engine speed may increase, then it will decrease
as needle is turned in (lean). Note position of
needle. Set adjusting needle midway between
rich and lean settings.
b. Repeat procedure on other low idle adjustment
needle.
3. Recheck/adjust Low Idle Speed (RPM) to specified
setting.
High Speed (RPM) Adjustment
1. With engine running, move throttle control to fast.
2. Turn inner adjustment screw outward to decrease, or
inward to increase RPM speed.
3. Stop when desired RPM speed is obtained.
Carburetor Servicing
Accidental Starts can cause severe injury or
death.
Disconnect and ground spark plug lead(s)
before servicing.
Before working on engine or equipment, disable
engine as follows: 1) Disconnect spark plug lead(s). 2)
Disconnect negative (–) battery cable from battery.
NOTE: Main and slow jets are fixed and side specific
and can be removed if required. Fixed jets for
high altitudes are available.
● Inspect carburetor body for cracks, holes, and other
wear or damage.
● Inspect float for cracks, holes, and missing or
damaged float tabs. Check float hinge and shaft for
wear or damage.
● Inspect fuel inlet needle and seat for wear or damage.
● Inspect spring loaded choke plate to make sure it
moves freely on shaft.
Float Replacement/Overhaul/Choke Repair
NOTE: Inlet needle center pin is spring loaded. Make
sure float rests against fuel inlet needle without
depressing center pin.
If symptoms described in Troubleshooting-Carburetor
Related Causes indicate float level problems, remove
carburetor from engine to check and/or replace float.
Use a float kit to replace float, pin, float valve, clip, and
screw.
62 690 01 Rev. J
WARNING
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1. Perform removal procedures for appropriate air
cleaner and carburetor outlined in Disassembly.
2. Clean exterior surfaces of dirt or foreign material
before disassembling carburetor. Remove screws
and carefully separate fuel bowl from carburetor. Do
not damage fuel bowl O-rings. Transfer any
remaining fuel into an approved container. Save all
parts. Fuel can also be drained prior to bowl removal
by loosening/removing bowl drain screw.
3. Remove screw and lift out old float, pin, and inlet
needle. Discard all of parts. Seat for inlet needle is
not serviceable and should not be removed.
4. Clean carburetor bowl and inlet seat areas as
required. To reassemble fuel bowl go to step 23,
otherwise go to step 5.
5. Carefully remove main jets from carburetor. Note
and mark jets by location for proper reassembly.
Main jets may be size/side specific. After main jets
are removed, main nozzles can be removed out
through bottom of main towers. Note orientation/
direction of nozzles. End with 2 raised shoulders
should be out/down adjacent to main jets. Save
parts for cleaning and reuse.
6. Remove screw securing flat washer and ground lead
(if equipped) from top of carburetor, then carefully
pull (lift) out slow jets. Slow jets may be sized/side
specific. Mark or tag jets for proper reassembly. Note
small O-ring on bottom of each jet. Save parts for
cleaning and reuse unless a jet kit is also being
installed. Clean slow jets using compressed air. Do
not use wire or carburetor cleaner.
7. Remove idle speed (RPM) adjustment screw and
spring from carburetor. Discard parts.
Carburetor is now disassembled for appropriate
cleaning and installation of parts in overhaul kit.
Further disassembly is not necessary. Throttle shaft
assembly, fuel inlet seat, idle fuel adjustment screws
with limiter, and carburetor body, are non-serviceable
items and should not be removed. Choke shaft
assembly is serviceable, however it should not be
removed unless a choke repair kit will be installed.
To install choke repair kit go to step 8, otherwise go
to step 18.
8. Remove and discard plastic cap from end of choke
lever/shaft assembly.
9. Note position of spring legs and choke plate for
correct reassembly later. Remove screws attaching
choke plate to choke shaft. Pull shaft out of
carburetor body, note preload of spring and discard
removed parts.
10. Use a screw extractor (easy-out) and remove
original choke shaft bushing with old choke lever
from carburetor housing. Save bushing to use as a
driver for installing new bushing. Discard old lever.
11. Clean I.D. of both choke shaft bores as required.
12. Insert new bushing through new choke lever from
outside and start bushing in outer shaft bore.
Position choke lever so protruding boss on
carburetor housing is between 2 stops formed in
choke lever.
Fuel System
33