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17
1. Start the engine and run at half throttle for 5 to
10 minutes to warm up. The engine must be
warm before doing steps 2, 3, and 4.
2. Place the throttle control into the idle or slow
position. Adjust the low idle speed to 1200 RPM*
Follow the Adjusting the Low Idle Speed (RPM)
procedure.
3. Low Idle Fuel Needle(s) Setting: Place the
throttle into the idle or slow position.
a. Turn one of the low idle fuel adjusting
needles out (counterclockwise) from the
preliminary setting until the engine speed
decreases (rich). Note the position of the
needle. Now turn the adjusting needle in
(clockwise). The engine speed may increase,
then it will decrease as the needle is turned
in (lean). Note the position of the needle. Set
the adjusting needle midway between the
rich and lean settings. See Figure 23.
b. Repeat the procedure on the other low idle
adjustment needle.
4. Recheck/adjust the Low Idle Speed (RPM), to the
specified setting.
Figure 21. Holding Throttle Lever Against Idle Stop
Screw.
Model CV750
CV750 engines use a Keihin BK two-barrel carburetor
with fixed main jets and fixed or limiter-equipped low
idle fuel adjusting needles. See Figure 22. Adjustments
are made as follows.
Hold Throttle
Lever Against
Screw
Figure 22. Keihin Two-Barrel Carburetor.
Low Idle Speed (RPM) Adjustment
1. Low Idle Speed (RPM) Setting: Place the throttle
control into the idle or slow position. Set the
low idle speed to 1200 RPM* (± 75 RPM) by
turning the low idle speed adjusting screw in or
out. Check the speed using a tachometer.
*NOTE: The actual low idle speed depends on the
application. Refer to the equipment
manufacturer’s recommendations. The low
idle speed for basic engines is 1200 RPM. To
ensure best results when setting the low idle
fuel needle, the low idle speed should be 1200
RPM (± 75 RPM).
Low Idle Fuel Adjustment
NOTE: Engines will have fixed low idle or limiter
caps on the two idle fuel adjusting needles.
Step 3 can only be performed within the
limits allowed by the cap. Do not attempt to
remove the limiter caps.
Low Idle Fuel
Adjusters
Low Idle
Speed (RPM)
Adjustment
Screw
Fuel Solenoid
Figure 23. Optimum Low Idle Fuel Settings.
An optional governed idle control system is supplied
on some CV750 engines. The purpose of this system is
to maintain a desired idle speed regardless of ambient
conditions (temperature, parasitic load, etc.) that may
change. Engines with this feature contain a small
secondary spring connected between the governor
lever and the lower adjustment tab of the main
bracket. See Figure 20. Refer to the same adjustment
procedure covered in Models with Governed Idle
System for the CV18-740 models on page 16, when
adjustments are required.
Lean
Rich
Adjust to
Midpoint
Lean
Rich
Adjust to
Midpoint
Left Side Right Side