Troubleshooting - Yard-Man YM70SS Operator's Manual

MAINTENANCE AND REPAIR INSTRUCTIONS
5. Clean the spark arrestor screen with a wire brush. Replace it if it is damaged, or if unable to clean it thoroughly.
6. Reinstall the spark arrestor screen snugly back into the spark arrestor hood.
7. Reinstall the two hood tabs into the two muffler slots and flip the spark arrestor hood closed.
8. Replace the screw removed in Step 2 and tighten it securely.
9. Reinstall the air filter/muffler cover.
WARNING:
If the spark arrestor hood and spark arrestor screen are not tightened securely, they
could fall off causing damage to the unit and possible serious personal injury.
CARBURETOR ADJUSTMENT
The idle speed of the engine is adjustable. An idle adjustment screw is between the air filter cover and the engine
starter housing (Fig. 26).
NOTE: Careless adjustments can seriously damage the unit. An authorized service dealer should make carburetor
adjustments.
Check Fuel Mixture
Old and/or improperly mixed fuel is usually the reason for improper unit performance. Drain and refill the tank with
fresh, properly-mixed 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.
Adjust Idle Speed Screw
WARNING:
The cutting attachment will spin during idle speed adjustments. 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 screw as follows:
1. Start the engine and run for one 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 screwdriver into the idle adjustment screw (Fig. 26). Turn the idle speed
screw clockwise 1/8 of a turn at a time (as needed) until the engine idles smoothly.
3. If the engine appears to be idling too fast, turn the idle speed screw
counterclockwise 1/8 of a turn at a time (as needed), to reduce idle speed.
Checking the fuel mixture, 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.
REPLACING THE SPARK PLUG
Use replacement #791-610311B, a Champion RDJ7Y 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.
WARNING:
Do not sand blast, scrape or clean electrodes. Grit in
the engine could damage the cylinder.
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. 27).
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
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.
LONG TERM STORAGE
If planning on storing the unit for an extended time, use the following storage procedure:
1. Drain all fuel from the fuel tank into a container with the same 2-cycle fuel mixture. Do not use fuel that has been
stored for more than 60 days. Dispose of the old fuel/oil mix in accordance to 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 1 oz. (30 ml) 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.
4
ENGINE WILL NOT START
Empty fuel tank
Primer bulb wasn't pressed enough
Engine is flooded
Old or improperly mixed fuel
Fouled spark plug
ENGINE WILL NOT IDLE
Air filter is plugged
Old or improperly mixed fuel
Improper carburetor adjustment
ENGINE WILL NOT ACCELERATE
Old or improperly mixed fuel
Cutting head bound with grass
Dirty air filter
ENGINE LACKS POWER OR STALLS
Old or improperly mixed fuel
Idle Adjustment Screw
Fouled spark plug
ENGINE STOPS WHILE IN USE
Engine overspeed protection engaged
CUTTING HEAD WILL NOT ADVANCE LINE
Fig. 26
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
0.025 in.
IF FURTHER ASSISTANCE IS REQUIRED, CONTACT AN AUTHORIZED SERVICE DEALER.
(0.635 mm.)
Fig. 27
ENGINE*
Engine Type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Air-Cooled, 2-Cycle
Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.25 in. (3.175 cm)
Displacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 cc
Operating RPM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6,800+ rpm
Idle Speed RPM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2,600 - 3,600 rpm
Ignition Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Electronic
Ignition Switch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rocker Switch
Spark Plug Gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.025 in. (0.635 mm)
Lubrication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fuel/Oil Mixture
Fuel/Oil Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40:1
Carburetor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diaphragm, All-Position
Starter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . EZ-Pull Version 3™
Muffler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Baffled with Guard
Throttle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Manual Spring Return
Fuel Tank Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 fl.oz. (296 ml)
DRIVE SHAFT AND CUTTING HEAD*
Drive Shaft Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Steel Tube
Throttle Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Finger-Tip Trigger
Total Approximate Unit Weight (without fuel) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 lbs. (6 kg)
Cutting Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bump Head™
Shoulder Strap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Optional
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

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SPECIFICATIONS
ACTION
Fill fuel tank with properly mixed fuel
Press primer bulb fully and slowly 10 times
With blue choke lever in position 3, squeeze the trigger
and pull the starter rope
Drain fuel tank and add fresh fuel mixture
Replace or clean the spark plug
ACTION
Replace or clean the air filter
Drain fuel tank and add fresh fuel mixture
Adjust according to the Carburetor Adjustments section
ACTION
Drain fuel tank and add fresh fuel mixture
Stop the engine and clean the cutting head
Clean or replace the air filter
ACTION
Drain fuel tank and add fresh fuel mixture
Replace or clean the spark plug
ACTION
Allow the engine to cool down for 10 minutes before
restarting.
ACTION
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
ACTION
Clean and thoroughly dry the cutting head