Starting/Stopping Instructions; Replacing The Spark Plug; Spark Arrestor Maintenance - Troy-Bilt TB590 EC Operator's Manual

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 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 in between the Air Filter Cover and the Engine Cover (Fig. 47).
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.
ROCKER ARM CLEARANCE
WARNING:
To avoid serious personal injury,
always turn the unit off and allow it to cool
before you clean or service it.
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
every 25 hours of operation.
• 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 six (6) screws on the back of the engine cover
with a Flat-head or T-25 Torx screwdriver (Fig. 48).
2. Disconnect the spark plug wire.
3. Clean dirt from around the spark plug. Remove the spark
plug from the cylinder head by turning a 5/8 in. socket
counterclockwise.
4. Remove the engine cover (Fig. 48).
5. Clean dirt from around the rocker arm cover. Remove the
screw holding the rocker arm cover with a large flat blade
screwdriver or Torx T-25 bit (Fig. 49). Remove the rocker
arm cover and gasket.
6. Pull the starter rope slowly to bring the piston to the top of
its travel, (known as top dead center). Check that:
• The piston is at the top of its travel while looking in the
spark plug hole (Fig. 49).
• Both rocker arms move freely, and both valves are closed.
If these statements are not true, repeat this step.
7. Slide the feeler gauge between the rocker arm and the
valve return spring. Measure the clearance between the
valve stem and rocker arm (Fig. 50). Measure both the
intake and exhaust valves.
The recommended clearance for both intake and exhaust is
.003 – .006 in. (.076 – 0.152 mm). Use a standard automotive
.005 in. (0.127 mm) feeler gauge. The feeler gauge should slide
between the rocker arm and valve stem with a slight amount of
resistance, without binding. See Figures 50 and 51.
8. If the clearance is not within specification:
a. Turn the adjusting nut using a 5/16 inch (8 mm) wrench or nut driver (Fig. 51).
• To increase clearance, turn the adjusting nut counterclockwise.
• To decrease clearance, turn the adjusting nut clockwise.
b. Recheck both clearances, and adjust as necessary.
9. Reinstall the rocker arm cover using a new gasket. Torque the screw to 20–30 in•lb (2.2–3.4 N•m).
10. Check the spark plug and reinstall. See Replacing the Spark Plug.
11. Replace the spark plug wire.
12. Reinstall the engine cover. Check alignment of the cover before tightening the screws. Tighten
screws.

REPLACING THE SPARK PLUG

Use a replacement part number 753-05255 or Champion® RDZ4H spark plug. The correct air gap is
0.025 in. (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. Remove the six (6)
screws on the back of the engine cover with a Flat-head or
T-25 Torx screwdriver (Fig. 48).
2. Grasp the plug wire firmly and pull the cap from the spark
plug.
WARNING:
Do not sand blast, scrape or clean
electrodes. Grit in the engine could damage the
cylinder.
3. Clean dirt from around the spark plug. Remove the spark
plug from the cylinder head by turning a 5/8 in. socket
counterclockwise.
4. Replace cracked, fouled or dirty spark plug. Set the air gap at 0.025 in. (0.635 mm) using a feeler
gauge (Fig. 52).
5. Install a correctly-gapped spark plug in the cylinder head. Turn the 5/8 in. 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.
8
MAINTENANCE AND REPAIR INSTRUCTIONS
Idle Adjustment Screw
Fig. 47
View Of The Rear Engine Cover
Screws Screws
Fig. 48
Rocker Arm Cover
Spark Plug
Hole
Fig. 49
Adjustment
Nuts
Intake
Rocker
Arms
Exhaust
Fig. 50
Rocker Arm
Adjusting Nut
Feeler
Gauge
0.003–0.006 in.
(0.076–0.152 mm)
Valve Stem
Fig. 51
0.025 in.
(0.635 mm)
Fig. 52

SPARK ARRESTOR MAINTENANCE

1. Remove the rear engine cover. See Rocker Arm Clearance.
2. With a flat blade screwdriver or Torx T-20 bit and a T-25 bit,
remove the screws attaching the spark arrestor cover to the
muffler (Fig. 53).
3. Pull the tab on the spark arrestor cover out of the muffler.
Remove the spark arrestor cover.
4. Remove the spark arrestor screen from the spark arrestor cover.
5. Clean the spark arrestor screen with a wire brush or replace it.
6. Reinstall the spark arrestor screen, spark arrestor cover and
screws.
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 the unit with fuel in the tank where fumes may reach an open flame or spark.
• Allow the engine to cool before storing.
• Lock up the unit 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
1. Drain all gasoline from the gas tank into a container. Do not use gas that has been stored for more
than 60 days. Dispose of the old gasoline in accordance to Federal, State, and Local regulations.
2. Start the engine and allow it to run until it stalls. This ensures that all gasoline has been drained
from the carburetor.
3. Allow the engine to cool. Remove the spark plug and put 5 drops of high quality motor 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
trimmer after storage.
4. Change the oil, referring to Changing the Oil. Dispose of the old oil in accordance to Federal, State
and Local regulations.
5. Thoroughly clean the unit and inspect for any loose or damaged parts. Repair or replace damaged
parts and tighten loose screws, nuts or bolts. The unit is ready for storage.
TRANSPORTING
• Allow the engine to cool before transporting.
• Secure the unit while transporting.
• Drain the gas tank before transporting.
• Tighten gas cap before transporting.
ELECTRIC STARTER AND POWER START BIT™ FEATURES
This unit is designed to be started with an optional electric starter or Power Start Bit™ that are sold
separately. If choosing to start the unit using one of these features or have questions please contact your
local retailer or call 1-800-828-5500 U.S, (1-800-668-1238 Canada), for more information and purchasing.
You may also go to www.troybilt.com or www.troybilt.ca.
Muffler
Spark Arrestor
Slot
T-20 Screw
Fig. 53
Electric Start Feature
Screen
Diverter
T-25
Screw