Cleaning And Storage; Troubleshooting Chart; Specifications - MTD YARD-MAN YM21CS Operator's Manual

MAINTENANCE AND REPAIR INSTRUCTIONS
REPLACING THE SPARK PLUG
WARNING:
Do not sand blast, scrape or clean electrodes. Grit in the engine could
damage the cylinder.
Use replacement #753-06193, a Champion RDJ7J spark plug, or equivalent.
The correct air gap is 0.025 inch (0.635 mm). Remove the plug after every 25
hours of operation and check its condition.
1. Stop the engine and allow it to cool. Grasp the plug wire firmly and pull
it from the spark plug.
2. Clean around the spark plug. Remove the spark plug from the cylinder head
by turning a 5/8-inch socket counterclockwise.
3. Replace a cracked, fouled or dirty spark plug. Set the air gap at 0.025 in.
(0.635 mm) using a feeler gauge (Fig. 25).
4. Install a correctly-gapped spark plug in the cylinder head. Tighten by turning the 5/8-inch socket
clockwise until snug.
If using a torque wrench torque to: 110-120 in.•lb. (12.3-13.5 N•m) Do not over tighten.

CLEANING AND STORAGE

CLEANING
WARNING:
To avoid serious personal injury, always turn the unit off and allow it to cool before you
clean or service it.
Use a small brush to clean off the outside of the unit. Do not use strong detergents. Household cleaners that contain
aromatic oils such as pine and lemon, and solvents such as kerosene, can damage plastic housing or handle. Wipe off
any moisture with a soft cloth.
STORAGE
• Never store a fueled unit where fumes may reach an open flame or spark.
• Allow the engine to cool before storing.
• Store the unit locked up to prevent unauthorized use or damage.
• Store the unit in a dry, well-ventilated area.
• Store the unit out of the reach of children.
Short Term Storage (1-2 weeks)
1. Store the unit in a horizontal position. If this is not possible, store the unit vertically with the engine at the top.
Long-term Storage
1. Remove the fuel cap, tip the unit and drain the fuel into an approved container.
NOTE: Do not use gasoline that has been stored for more than 30 days. Dispose of old gasoline in accordance with
federal, state and local regulations.
2. Start the engine and allow it to run until it stalls. This ensures that all fuel has been drained from the carburetor.
3. Allow the engine to cool. Remove the spark plug and put 5 drops of any high quality motor oil or 2-cycle oil into the
cylinder. Pull the starter rope slowly to distribute the oil. Reinstall the spark plug.
NOTE: Remove the spark plug and drain all of the oil from the cylinder before attempting to start the unit after storage.
4. Thoroughly clean the unit and inspect it for any loose or damaged parts. Repair or replace damaged parts and
tighten loose screws, nuts or bolts. The unit is ready for storage.
ENGINE WILL NOT START
Empty fuel tank
The primer bulb wasn't pressed enough
Engine is flooded
The fuel is old (over 30 days) and/or improperly mixed
Fouled spark plug
0.025 in.
ENGINE WILL NOT IDLE
(0.635 mm.)
Air filter is plugged
Fig. 25
The fuel is old (over 30 days) and/or improperly mixed
Improper idle speed
ENGINE WILL NOT ACCELERATE
The fuel is old (over 30 days) and/or improperly mixed
Cutting head bound with grass
Dirty air filter
ENGINE LACKS POWER OR STALLS
The fuel is old (over 30 days) and/or improperly mixed
Fouled spark plug
CUTTING HEAD WILL NOT ADVANCE LINE
Cutting head bound with grass
Cutting head out of line
Inner reel bound up
Cutting head dirty
Line welded
Line twisted when refilled
Not enough line is exposed
CUTTING LINE ADVANCES UNCONTROLLABLY
Oil, cleaner or lubricant in cutting head
IF FURTHER ASSISTANCE IS REQUIRED, CONTACT AN AUTHORIZED SERVICE DEALER.
Engine Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Air-Cooled, 2-Cycle
Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.10 in. (2.6 cm)
Displacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 cc
Operating RPM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6,300 + rpm
Idle Speed RPM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,800 - 3,400 rpm
Spark Plug Gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.025 in. (0.635 mm)
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fuel/Oil Mixture
Fuel/Oil Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40:1
Fuel Tank Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 fl. oz. (296 ml)
Approximate Unit Weight (No fuel, with cutting attachment, shield and D-handle) 10 - 11 lbs. (4.5 - 5 kg)
Cutting Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bump Head™
Line Spool Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 in. (76.2 mm)
Trimming Line Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.095 in. (2.41 mm)
Cutting Path Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 in. (43.18 cm)
* All specifications are based on the latest product information available at the time of printing. We
reserve the right to make changes at any time without notice.
TROUBLESHOOTING
CAUSE

SPECIFICATIONS

ACTION
Fill fuel tank with properly mixed fuel
Press the primer bulb 10 times or until fuel is visible
With the choke lever in position 3, squeeze the trigger
and pull the starter rope
Drain the fuel tank and add fresh, properly mixed fuel
Replace or clean the spark plug
Replace or clean the air filter
Drain the fuel tank and add fresh, properly mixed fuel
Adjust the idle speed
Drain the fuel tank and add fresh, properly mixed fuel
Stop the engine and clean the cutting head
Clean or replace the air filter
Drain the fuel tank and add fresh, properly mixed fuel
Replace or clean the spark plug
Stop the engine and clean cutting head
Refill with new line
Rewind the inner reel
Clean inner reel and outer spool
Disassemble, remove the welded section and rewind
Disassemble and rewind the line
Push the bump knob and pull out line until 4 inches (102 mm)
of line is outside of the cutting head
Clean and thoroughly dry the cutting head
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