Service Manual

Figure 1-10. Carburetor Adjustments.
1. Initial Idle Speed Setting: Turn idle speed screw
counterclockwise until it does not touch the throttle
lever. Now turn the screw clockwise until it just
touches the throttle lever; then continue turning 2
full turns.
2. If so equipped, remove the rubber cap from the
high speed mixture adjustment needle.
3. Initial High Speed Mixture and Idle Mixture Settings:
Turn both the high speed mixture and idle mixture
needles clockwise until they are lightly seated.
Then turn the needles counterclockwise the
following number of turns:
High Speed Mixture Needle : 1¼ turns
Idle Mixture Needle: 1¼ turns
NOTE: Turn the high speed mixture and idle
mixture needles finger-tight. Do not force the
needles with a screw driver as this can damage
the tips of the needles and the seats in the
carburetor body.
4. Start engine and allow it to warm up for 3 to 5
minutes.
NOTE: For the following steps, use a magnetic
pick-up 2-cycle engine tachometer to monitor
engine speed.
5. Final High Speed Mixture Setting: Squeeze the
throttle trigger to the FULL (WIDE OPEN)
THROTTLE position. Turn the high speed mixture
needle clockwise or counterclockwise to set the
high speed RPM: 6,800 to 7,200.
6. Release the throttle trigger and let the engine idle.
If the engine stops, turn the idle speed screw
clockwise 1/8 turn at a time until the engine idles.
7. Final Idle Mixture and Idle Speed Settings: Adjust
the the idle mixture and idle speed as follows:
a. Turn the idle mixture needle clockwise until the
fastest idle RPM is reached; then turn the
needle counterclockwise 1/8 turn.
b. Squeeze the throttle trigger. If the engine falters
or hesitates as it accelerates, turn the idle
mixture needle counterclockwise 1/16 turn at
a time until the engine accelerates rapidly.
c. If the idle speed has changed significantly
because of steps a. and b. above, readjust the
idle speed screw.
The recommended idle speed for all products is
3,000 to 3,200 RPM.
8. Make sure the air filter cover is reinstalled securely
before placing the unit back into service.
Governed Carburetor Check
Some units are equipped with fuel-governed
carburetors. If so equipped, and after adjusting the
carburetor, check the operation of the governor on
trimmers and brush cutters as follows:
1. Clip or wind the cutting line so it is inside the cutting
head (not extended to its full cutting length).
2. Start the engine and run it at FULL (WIDE OPEN)
THROTTLE.
The maximum high speed RPM should not exceed
8,800 RPM.
3.6069.010
(H) High
Speed
Mixture
(L) Idle Mixture
Needle
Idle
Speed
Screw
1
GENERAL INFORMATION
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