McCulloch MB2500BP, User Manual

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8 - MAINTENANCE INSTRUCTIONS
8-5. SPARK PLUG
1. To remove spark plug (A) (Fig. 8-5A) for cleaning or
replacement: make sure engine is off, spark plug is
cool, then grasp spark plug boot firmly and remove
from spark plug. Remove spark plug with correct spark
plug tool. Inspect, clean or replace as needed.
2. Spark plug gap = .025" (.635mm) (Fig
.
8-5B).
3. Torque to 120 inch pounds (12 to 15 N•m). Connect
spark plug boot.
4. If needed, replace spark plug with Champion RZ7C or
equivalent.
8-6. STORAGE
Failure to follow these steps may cause varnish to form in
the carburetor which can cause difficult starting or perma-
nent damage following storage.
1. Perform all the general maintenance recommended in
the Maintenance Section of your User Manual.
2. Clean exterior of engine and blower tubes.
3. Drain fuel from the fuel tank by running the unit dry or
by removing the fuel cap and tipping the motor hous-
ing/fuel tank over and draining oil/fuel mixture into a
container with the same 2-cycle fuel mixture.
4. After fuel is drained, start engine.
5. Run engine at idle until unit stops. This will purge the
carburetor of fuel.
6. Allow engine to cool (approx. 5 minutes).
7. Using a spark plug wrench, remove the spark plug.
8. Pour 1 teaspoon of clean 2-cycle oil into the
combustion chamber. Pull starter rope slowly several
times to coat internal components. Replace spark plug.
9. Store unit in a cool, dry place away from any source of
ignition such as an oil burner, water heater, etc.
8-7. REMOVING A UNIT FROM STORAGE
1. Remove spark plug.
2. Pull starter rope briskly to clear excess oil from com-
bustion chamber.
3. Clean and gap spark plug or install a new spark plug
with proper gap. (Fig. 8-5
B
)
4. Prepare unit for operation.
5. Fill fuel tank with proper fuel / oil mixture. See Fuel and
Lubrication Section.
8-5B
8-5A
A
.025" (.635mm)
Spark
Plug
CORRECTIVE ACTION
Follow instructions in the User Manual.
Have carburetor adjusted by an
Authorized Service Center.
Clean / gap or replace plug.
Replace fuel filter.
Move to RUN position.
Replace spark arrester screen.
Remove, clean and reinstall filter.
Have carburetor adjusted by an
Authorized Service Center.
Have carburetor adjusted by an
Authorized Service Center.
Clean / gap or replace plug.
Have carburetor adjusted by an
Authorized Service Center.
Use properly mixed fuel (40:1 mixture).
PROBLEM
Unit won’t start or starts but will not
run.
Unit starts, but engine has low
power.
Engine hesitates.
No power under load.
Runs erratically.
Smokes excessively.
PROBABLE CAUSE
Incorrect starting procedures.
Incorrect carburetor mixture adjustment
setting.
Fouled spark plug
Fuel filter plugged.
Incorrect lever position on choke.
Dirty spark arrester screen.
Dirty air filter.
Incorrect carburetor mixture adjustment
setting.
Incorrect carburetor mixture adjustment
setting.
Incorrectly gapped spark plug.
Incorrect carburetor mixture adjustment
setting.
Incorrect fuel mixture.
9 - TROUBLESHOOTING THE ENGINE