Chapter 1: INTRODUCTION
4
3. Cleaning the spark plug:
NOTE: MTD does not recommend cleaning
spark plugs. Use of a wire brush may leave
metal deposits on the insulator that causes the
spark plug to short out and fail to spark. Use of
abrasive blast for cleaning may cause damage
to ceramic insulator or leave blast media in the
recesses of the spark plug. When the media
comes loose during engine operation, severe
and non-warrantable engine damage may result.
4. Inspection of the spark plug can provide indica-
tions of the operating condition of the engine.
• Light tan colored deposits on insulator and elec-
trodes is normal.
• Dry, black deposits on the insulator and elec-
trodes indicate an over-rich fuel / air mixture (too
much fuel or not enough air)
• Wet, black deposits on the insulator and elec-
trodes indicate the presence of oil in the com-
bustion chamber.
• Heat damaged (melted electrodes / cracked
insulator / metal transfer deposits) may indicate
detonation.
• A spark plug that is wet with fuel indicates that
fuel is present in the combustion chamber, but it
is not being ignited.
Oil type and capacity
1. To check the oil, twist and remove the dip stick
from the engine. Clean the oil off of the tip of the
dipstick. Re-insert the dipstick without threading
it in to get the oil level reading.
See Figure 1.3.
• SAE 5W-30 oil with a SF/SG API rating or better
is the recommended oil for this engine.
• The oil capacity is 37 fl.oz (1.1 liters).
2. The oil level is determined by the lowest point on
the dipstick that is completely covered with oil.
3. If the oil is noticeably thin, or smells of gasoline,
a carburetor repair may be needed before the
engine can be run safely.
• Check the oil level frequently and change the oil
more frequently in severe operating conditions
such as exceptionally deep snow falls.
• Synthetic oil is a suitable alternative, but it does
not extend service intervals.
NOTE: MTD recommends the use of petroleum
oil during the break in period to ensure the piston
rings correctly break in.
• Synthetic vs. Petroleum based oil: To simply look
at synthetic oil and to compare it with Petroleum
based oil there is very little difference. However,
when you look at the two through a microscope it
is easy to see the difference. Synthetic is made
up of smaller molecules. This allows the oil to
get into areas that petroleum based oil cannot.
Figure 1.3
Do not thread
dipstick in to check
the oil level