MTD YM26BC - Manual (Page 22)

22
SECTION 7: MAINTENANCE AND REPAIR INSTRUCTIONS
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.
Adjust Idle Speed
WARNING: The cutting attachment may
spin during idle speed adjustments. Wear
protective clothing and observe all safety
instructions to prevent serious personal
injury.
If, after checking the fuel and cleaning the air filter, the
engine still will not idle, adjust the idle speed screw as
follows:
1. Start the engine and let it run at a high idle for a minute
to warm up. Refer to Starting/Stopping Instructions.
2. Release the throttle trigger and let the engine idle. If the
engine stops, insert a small phillips or flat blade screwdriver
into the hole in the air filter/muffler cover. See Figure 49.
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 attachment should not rotate when
the engine idles.
3. If the cutting attachment 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.
Checking the fuel, cleaning the air filter, and adjusting the
idle speed should solve most engine problems. If not and
all of the following are true:
• 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 turning the unit off, make
sure the cutting attachment has stopped
before setting the unit down. This helps
prevent serious personal injury.
Idle Adjustment Screw
Remove Screws
Engine Cover
2. Remove the two (2) screws on top of the engine cover
with a Flat-head or T-25 Torx screwdriver. See Figure 51.
Engine Cover
Muffler
Rocker Arm Clearance
This 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.
1. Remove the muffler cover by pressing down on it,
separating it from the engine cover. Using a flat
blade screwdriver, disengage the middle and front
tabs and slots first. The cover will hinge off from the
rear tab. See Figure 50.
Top View Of The Engine
Front Slot
Front Tab
Middle Tab
Middle Slot
Rear Slot
and Tab
Figure 49
Figure 51
Figure 50