McCulloch 966992201 Troubleshooting The Engine, Carburetor Adjustment, Spark Plug, Storing A Unit

7 - MAINTENANCE INSTRUCTIONS

8 - TROUBLESHOOTING THE ENGINE

7-4. CARBURETOR ADJUSTMENT

The carburetor was pre-set at the factory for optimum per- formance. The only adjustment should be to idle speed see section 5-4, Idling/Carburetor adjustment.

7-5. SPARK PLUG

1.To remove spark plug B (figure 7-6A) 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) (Figure 7-5A).

3.Torque to 105 to 130 inch pounds (12 to 15 N•m). Connect spark plug boot.

4.If necessary, replace with Champion RZ7C or equiva- lent.

.025" (.635mm)

7-5A

7-6. SPARK ARRESTER SCREEN

1.To replace spark arrester screen (A) (Figure 7-6A), use a needle nose pliers, pinch an edge of the spark arrester screen. Pull the whole spark arrester screen out.

2.Use the needle nose pliers to push in a new spark arrester screen. Then open the pliers a little to press the inner surface of the spark arrester screen to fasten it.

B

A

7-6A

7-7. DEBRIS SHIELD KNIFE SHARPENING

1.Remove cutter knife (A) from debris shield (B) (Figure 7-7A).

2.Place knife in a bench vise. Sharpen knife using a flat file, being careful to maintain the angle of cutting edge. File in one direction only.

A

B

7-7A

7-8. STORING A UNIT

Failure to follow these steps may cause varnish to form in the carburetor and 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, drive shaft assembly, debris shield and stringhead.

3.Drain fuel from the fuel tank.

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.

7-9. 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.

4.Prepare unit for operation.

5.Fill fuel tank with proper fuel / oil mixture. See Fuel and Lubrication Section.

PROBLEM	PROBABLE CAUSE	CORRECTIVE ACTION
	Incorrect starting procedures.	Follow instructions in the User Manual.
	Incorrect carburetor mixture adjustment	Have carburetor adjusted by an
	setting.	McCulloch Authorized Service Center.
Unit won’t start or starts but will not run.
	Fouled spark plug	Clean / gap or replace plug.
	Fuel filter plugged.	Replace fuel filter.
	Incorrect lever position on choke.	Move to RUN position.
	Dirty spark arrester screen.	Replace spark arrester screen.
Unit starts, but engine has low power.
	Dirty air filter.	Remove, clean and reinstall filter.
	Incorrect carburetor mixture adjustment	Have carburetor adjusted by an
	setting.	McCulloch Authorized Service Center.
Engine hesitates.
	Incorrect carburetor mixture adjustment	Have carburetor adjusted by an
	setting.	McCulloch Authorized Service Center.
No power under load.
Runs erratically.	Incorrectly gapped spark plug.	Clean / gap or replace plug.
	Incorrect carburetor mixture adjustment	Have carburetor adjusted by an
	setting.	McCulloch Authorized Service Center.
Smokes excessively.
	Incorrect fuel mixture	Use properly mixed fuel (40:1 mixture).

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