Maintaining your engine, Warning – Cub Cadet 18M User Manual
Page 22

3. Measure the plug gap with a feeler gauge. Correct
as necessary by bending side electrode. See Figure 
10-4. The gap should be set to 0.030 in.
4. Check that the spark plug washer is in good condi-
tion 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.
IMPORTANT: The spark plug must be securely tight-
ened. An improperly tightened spark plug can become 
very hot and may damage the engine.
Clean Engine
If the engine has been running, allow it to cool for at 
least half an hour before cleaning. Periodically remove 
grass and dirt build-up from engine. Clean finger guard 
and around muffler. Clean with a brush or compressed 
air.
IMPORTANT: 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 air cleaner or muffler opening. Water in 
the air cleaner will soak the paper element, and water 
that passes through the element or muffler can enter the 
cylinder, causing damage.
WARNING: Accumulation of debris 
around muffler could cause a fire. 
Inspect and clean before every use.
Storage
Engines stored over 30 days need to be drained of fuel 
to prevent deterioration and gum from forming in fuel 
system or on essential carburetor parts. If the gasoline in 
your engine deteriorates during storage, you may need to 
have the carburetor, and other fuel system components, 
serviced or replaced.
1. Remove all fuel from tank by running engine until it 
stops from lack of fuel.
2. Change oil. See Oil Change section.
3. Remove spark plug and pour about 1/2 an ounce of 
engine oil into cylinder. Replace spark plug and crank 
slowly to distribute oil.
4. Clean grass and debris from around engine, under
finger guard, and under, around and behind muffler. 
Touch up any damaged paint, and coat other areas 
that may rust with a light film of oil.
5. Store in a clean, dry and well ventilated area away from
any appliance that operates with a flame or pilot light, 
such as a furnace, water heater, or clothes dryer. Also 
avoid any area with a spark producing electric motor, 
or where power tools are operated.
6. If possible, also avoid storage areas with high humidity,
because that promotes rust and corrosion.
7. Keep the engine level in storage. Tilting can cause fuel
or oil leakage.
Removing From Storage
1. Check your engine as described in the Pre-Operation
Check section of this manual.
2. If the fuel was drained during storage preparation, fill
the tank with fresh gasoline. If you keep a container 
of gasoline for refueling, make certain it contains only 
fresh fuel. Gasoline oxidizes and deteriorates over 
time, causing hard starting.
3. If the cylinder was coated with oil during storage
preparation, the engine will smoke briefly at startup. 
This is normal.
10
Maintaining
Your
Engine
WARNING
Accumulation of
debris around muffler
could cause a fire.
Inspect and clean
before every use.
IMPORTANT: 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 
air cleaner or muffler 
opening. Water in the 
air cleaner will soak 
the paper element, 
and water that passes 
through the element 
or muffler can enter 
the cylinder, causing 
damage.
Figure 10-4: Measure the plug gap with a feeler gauge.
Electrode
0.030 in.
