Zenoah CHTZ2401 Workshop Manual page 25

Rich Down Adjustment
Throttle Valve
Adjust Screw
Rich Down:
Adjust the idle needle to a slightly richer mixture in order to
maintain a stable idling speed and get a good acceleration.
Set engine speed
Confirmation after adjustment
7. Carburetor Service Guide
L-needle
Best
Rich Down
Peak
(rpm)
Peak engine speed
Dust Cover
Limiter Cap
1. Turn the idling limiter (L-needle) clockwise (CW) to
the position of maximum engine speed. (Peak)
2. Turn the throttle valve adjust screw in either
direction to match to the regulated ID peak speed.
(Refer to page 15 "5. Carburetor Specifications- ID
Peak Engine Speed".)
3. Turn the L-needle counterclockwise (CCW) and
execute the rich down adjustment.
(Refer to page 15 "5. Carburetor Specifications- ID
Rich Down".)
4. Turn the throttle valve adjust screw in either
direction and set the ID speed.
(Refer to page 15 "5. Carburetor Specifications-
Set ID Engine Speed".)
5. Check that rotational speed accelerates normally
between idling state and full throttle within the
regulated number of revolutions.
(Refer to page 15 "5. Carburetor Specifications-
Standard Engine Speed".)
.
● For some models: After adjustment is completed,
be sure to install the new limiter cap.
(Refer to page 18 "7-3 Limiter Cap Removal/
Installation".)
● Be sure to reattach the dust cover.
Caution:
If the engine is run while the throttle valve's
dust cover is removed, dust or alien matter
may adhere to the throttle valve's rear
contoured or the plunger contacting surfaces.
If they become worn, the L-needle will fall
causing engine start failure.
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