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Idle Speed Screw
FIGURE 26
CARBURETOR SETTING
The idle speed of the engine is adjustable through the
air filter/muffler cover. See Figure 26.
NOTE: Careless adjustments can seriously damage
your unit. An authorized service dealer
should make carburetor adjustments.
Check Fuel Mixture
Old or dirty fuel is usually the reason for improper
unit performance. Drain and refill the tank with fresh
fuel prior to making any adjustments. Refer to Oil and
Fuel Information.
Clean Air Filter
The condition of the air filter is important to the
operation of the unit. A dirty air filter will restrict air
flow and change the air/fuel mixture. This is often
mistaken for an out of adjustment carburetor. Check the
condition of the air filter before adjusting the idle speed
screw. Refer to Air Filter Maintenance.
Adjusting the Idle Speed
WARNING: The cutting head may spin during
idle speed adjustment. Wear protective
clothing and observe all safety instructions to
prevent serious personal injury.
If, after checking the fuel mixture and cleaning the air
filter, the engine still will not idle, adjust the idle speed
as follows:
1. Start the engine and let it run at a high idle for a
minute to warm up.
2. Release the throttle trigger and let the engine idle.
If the engine stops, engage the idle speed screw
with a small screwdriver. See figure 26. Turn the
idle speed screw in, clockwise, 1/8 of a turn at a
time (as needed) until the engine idles smoothly.
NOTE: The cutting head should not rotate when the
engine idles.
3. If the cutting head rotates when the engine idles,
turn the idle speed screw counterclockwise 1/8 of a
turn at a time (as needed) to reduce idle speed.
These procedures should solve most engine problems.
If this isn’t the case, and:
• The engine will not idle
• The engine hesitates or stalls on acceleration
• There is a loss of engine power
Have the carburetor adjusted by an authorized service
dealer.
WARNING: After the unit is turned off,
make sure the cutting head has stopped
before you set down the unit. This will help
prevent serious personal injury.
MAINTENANCE & REPAIR INSTRUCTIONS
19
ROCKER ARM CLEARANCE
This procedure requires disassembly of the engine. If
you feel unsure or unqualified to perform this, take the
unit to an authorized service center.
NOTE: Inspect the valve to rocker arm clearance
with a feeler gauge after the first 10 hours of
operation and then every 25 hours of
operation thereafter.
• The engine must be cold when checking or
adjusting the valve clearance.
• This task should be performed inside, in a clean,
dust free area.