Servicing The Air Cleaner; Cleaning The Engine - Sears Craftsman 450 Serie Manual De Uso

1. Remove the spark plug boot and use a spark plug wrench to remove the
plug. See Figure 21.
Spark Plug
2. Visually inspect the spark plug. Discard the spark plug if there is apparent
wear, or if the insulator is cracked or chipped. Clean the spark plug with a
wire brush if it is to be reused.
3. Measure the plug gap with a feeler gauge. Correct as necessary by bending
side electrode. See Figure 22. The gap should be set to 0.030 in.
Electrode
0.02-0.03 in.
0.60-0.80 mm
4. Check that the spark plug washer is in good condition and thread the spark
plug in by hand to prevent cross-threading.
5. After the spark plug is seated, tighten with a spark plug wrench to compress
the washer.
NOTE: When installing a new spark plug, tighten 1⁄2 turn after the spark
plug seats to compress the washer. When reinstalling a used spark plug,
tighten 1⁄8-1⁄4 turn after the spark plug seats to compress the washer.
The spark plug must be securely tightened. An improperly tightened spark
plug can become very hot and may damage the engine.
SERVICE AND MAINTENANCE
Spark Plug
Boot
Figure 21
Figure 22
CAUTION

Servicing the Air Cleaner

Never use gasoline or low flash point solvents for cleaning the air cleaner
element. A fire or explosion could result.
The air cleaner prevents damaging dirt, dust, etc., from entering the carburetor and
being forced into the engine and is important to engine life and performance. Never
run the engine without an air cleaner completely assembled. Check the air cleaner
before each use.
Paper filters cannot be cleaned and must be replaced once a year or every 100
operating hours; more often if used in extremely dusty conditions.
1. Press the tab on the air filter cover, lift the cover and remove the air filter.
See Figure 23.
Air Filter
Cover
Air Filter
2. Discard old air filter.
3. Install new air filter.
4. Close the cover.
NOTE: If the filter is torn or damaged in any way, replace it.

Cleaning the Engine

Do not spray engine with water to clean because water could contaminate
fuel. Using a garden hose or pressure washing equipment can also force
water into the muffler opening. Water that passes through the muffler can
enter the cylinder, causing damage.
Accumulation of debris around muffler could cause a fire. Inspect and
clean before every use.
If the engine has been running, allow it to cool for at least half an hour before
cleaning. Periodically remove dirt build-up from the engine. Clean around the
muffler. Clean with a brush or compressed air.
17
WARNING
Foam Element
Figure 23
CAUTION
WARNING