Cub Cadet ST228 Holding the Trimmer, Refer to, Starting/Stopping Instructions, SEE, Fig, Fig, Fig, Fig, Air, Tab, Fig, Fig, Fig, Bump, Knob, NOTE:, NOTE:, NOTE:, NOTE:, NOTE:

OPERATING INSTRUCTIONS

HOLDING THE UNIT
WARNING: Always wear eye, hearing, foot
and body protection to reduce the risk of injury
when operating this unit.
Before operating the unit, stand in the operating position
(Fig. 23). Check for the following:
• The operator is wearing eye protection and proper clothing
• With a slightly-bent right arm, the operator’s hand is
holding the shaft grip
• The operator’s left arm is straight, the left hand holding
the D-handle
• The unit is at waist level	Fig. 23

•The cutting head is parallel to the ground and easily contacts the grass without the need to bend over

ADJUSTING TRIMMING LINE LENGTH

WARNING: Do not remove or alter the line cutting blade assembly. Excessive line length will cause premature engine failure and / or unit damage.

The Bump Head™ cutting head allows the release of trimming line without stopping the engine. To release more line, lightly tap the cutting head on the ground (Fig. 24) while operating the unit at high speed.

NOTE: Always keep the trimming line fully extended. Line release becomes more difficult when the cutting line gets shorter.

Each time the head is bumped, about 1 inch (25.4 mm) of trimming line releases. A blade in the cutting head shield will cut the line to the proper length if any excess line is released.

For best results, tap the bump knob on bare ground or hard soil. If attempting
a line release in tall grass, the engine may stall. Always keep the trimming line
fully extended. Line release becomes more difficult when the cutting line gets	Fig. 24
shorter.

NOTE: Do not rest the Bump Head™ on the ground while the unit is running.

Some line breakage will occur from:

•Entanglement with foreign matter

•Normal line fatigue

•Attempting to cut thick, stalky weeds

•Forcing the line into objects such as walls or fence posts

TIPS FOR BEST TRIMMING RESULTS

•Keep the cutting head parallel to the ground.

•Do not force the cutting head. Allow the tip of the line to do the cutting, especially along walls. Cutting with more than the tip will reduce cutting efficiency and may overload the engine.

•Cut grass over 8 inches (200 mm) by working from top to bottom in small increments to avoid premature line wear or engine drag.

•Cut from right to left whenever possible. Cutting to the left improves the unit's cutting efficiency. Clippings are thrown away from the operator.

•Slowly move the unit into and out of the cutting area at

the desired height. Move either in a forward-backward or side-to-side motion. Cutting shorter lengths produces the best results.

• Trim only when grass and weeds are dry.

• The life of the cutting line is dependent upon:

•	Following the trimming techniques
•	What vegetation is being cut
•	Where vegetation is cut
For example, the line will wear faster when trimming against
a foundation wall as opposed to trimming around a tree.		Fig. 25

DECORATIVE TRIMMING

Decorative trimming is accomplished by removing all vegetation around trees, posts, fences, etc.. Rotate the whole unit so that the cutting head is at a 30° angle to the ground (Fig. 25).

USING THE CUTTING BLADE

WARNING: Always wear eye, hearing, foot, body protection and the shoulder strap to reduce the risk of injury when operating this unit.

WARNING: Do not use the cutting blade for edging or as an edger. Severe personal injury to yourself or others can result.

Before operating the unit with the cutting blade, stand in the operating position (Fig. 26). Refer to Holding the Trimmer.

Cutting Blade Operating Tips

WARNING: Blade thrust may occur when the spinning blade contacts an object that it does not immediately cut. Blade thrust can be violent enough to cause the unit and/or operator to be propelled in any direction, and possibly lose control of the unit. Blade thrust can occur without warning if the blade snags, stalls or binds. This is more likely to occur in areas where it is difficult to see the material being cut.

To establish a rhythmic cutting procedure:

•	Plant feet firmly, comfortably apart.
•	Bring the engine to full throttle before entering the
	material to be cut. At full throttle the blade has maximum
	cutting power and is less likely to bind, stall or cause
	blade thrust (which can result in serious personal injury
	to the operator or others).
•	Cut while swinging the upper part of your body from left
	to right.
•	Always release the throttle trigger and allow the engine to
	return to idle speed when not cutting.
•	When you are finished, always unsnap the unit from the	Fig. 26
	harness before taking off the harness.

•Swing the unit in the opposite direction as the blade spins, which increases the cutting action.

•After the return swing, move forward to the next area to be cut and plant your feet again.

•The cutting blade is designed with a second cutting edge. You can use it by removing the blade, turning it upside down and reinstalling it.

To reduce the chance of material wrapping around the blade, follow these steps:

WARNING: The blade continues to spin after the engine is turned off. The coasting blade can seriously cut you if accidentally touched.

• Cut at full throttle.

• Swing the unit into material to be cut from your left to your right (Fig. 27).

• Avoid the material just cut as you make the return swing.

WARNING: Do not clear away any cut material
with the engine running or blade turning. To avoid
serious personal injury, turn off the engine. Allow
the blade to stop before removing materials
wrapped around the blade shaft.	Fig. 27

MAINTENANCE AND REPAIR INSTRUCTIONS

MAINTENANCE SCHEDULE

WARNING: To prevent serious injury, never perform maintenance or repairs with unit running. Always service and repair a cool unit. Disconnect the spark plug wire to ensure that the unit cannot start.

Perform these required maintenance procedures at the frequency stated in the table. These procedures should also be a part of any seasonal tune-up.

NOTE: Some maintenance procedures may require special tools or skills. If you are unsure about these procedures take your unit to any non-road engine repair establishment, individual or authorized service dealer.

NOTE: Maintenance, replacement, or repair of the emission control devices and system may be performed by any non-road engine repair establishment, individual or authorized service dealer.

NOTE: Please read the California/EPA statement that came with the unit for a complete listing of terms and coverage for the emissions control devices, such as the spark arrestor, muffler, carburetor, etc.

FREQUENCY	MAINTENANCE REQUIRED	SEE
Before starting engine	Fill fuel tank with fresh fuel	p. 4
Every 10 hours	Clean and re-oil air filter	p. 5
Every 25 hours	Check spark plug condition and gap	p. 5

REMOVING THE LINE

WARNING: Never use metal-reinforced line, wire, chain or rope. These can break off and become dangerous projectiles.

1.	Rotate the bump knob clockwise until all line is	Bump	Flat-Head
	inside the cutting head (Fig. 28).	Knob	Screw Driver
2.	Using a flat-head screwdriver, insert the tip into
	the line dimple and just under the exposed
	portion of the line (Fig. 29)
3.	Pull the line straight out until all line is removed		Trimmer
	from the cutting head.
			Line
			Dimple
		Fig. 28	Fig. 29

LINE INSTALLATION

Always use original equipment manufacturer 0.095 in. (2.41 mm) replacement line.

1.Align the arrows on the bump knob with the spool cover eyelets, if they are not already (Fig. 30).

2.Using 16 ft. (4.8 m) of 0.095 in. (2.41 mm)

replacement line push both ends of the line	Arrows
through the holes in the bump knob until they
protrude through the eyelets on both sides of the
cutting head. Continue pulling the line until
approximately 8 ft. (2.4 m) is visible from both
sides of the cutting head. (Fig. 31)
3. Hold the spool cover, turn the bump knob
clockwise to wind the line around the spool	Eyelet	Trimmer Line
until about 5 in. (12.7 cm) is protruding from	Fig. 30	Fig. 31
each side of the cutting head. (Fig. 31)

4.Start the unit and bump the cutting head on the ground until the desired cutting length is achieved. Excess line will be trimmed off by the line blade.

NOTE: If the cutting line ends are pulled into the cutting head or the line becomes twisted, refer to Removing the Line.

AIR FILTER MAINTENANCE

WARNING: To avoid serious personal injury, always turn the unit off and allow it to cool before you clean or service it.

Cleaning the Air Filter
Failure to maintain your air filter properly can result in poor performance or can cause permanent
damage to your engine.		Tab Lock
1.	Open the air filter cover. Push the locking tab on the top of the cover
		Air
	inward, then pull the air filter cover out and down. (Fig. 32).	Filter
2.	Remove the air filter (Fig. 32).	Air Filter
3.	Wash the filter in detergent and water. Rinse the filter thoroughly and
		Cover
	allow it to dry.
		Tab
4.	Apply enough clean SAE 30 motor oil to lightly coat the filter.
5.	Squeeze the filter to spread and remove excess oil.	Fig. 32
6.	Replace the filter.

NOTE: If the unit is operated without the air filter, you will VOID the warranty.

7.Reinstall the air filter cover. Position the slots on the bottom of the air filter cover onto the tabs at the bottom of the back plate (Figs. 32).

8.Swing the cover up until the tab on the air filter backplate snaps into place in the slot on the air filter cover (Fig. 32).

IDLE SPEED 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. 33).

NOTE: Careless adjustments can seriously damage the unit. An authorized service dealer should make carburetor adjustments.

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	Idle Adjustment Screw
	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. 33).
	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	Fig. 33
	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 #753-06193, a Champion® RDJ8J spark plug, or equivalent. The correct air gap is 0.025 inch (0.635 mm).

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.	0.025 in.
	(0.635 mm) using a feeler gauge (Fig. 34).	(0.635 mm.)
4.	Install a correctly-gapped spark plug in the cylinder head. Tighten by		Fig. 34
	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.

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