Engine Manual

Operator’s Manual
Viper® 173cc 4-Cycle Engine
13
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AIR FILTER
Refer to maintenance schedule for suggestions on when to service
your air lter. Washing lter is not recommended. When dirty,
replace lter (Viper P/N 10905).
Removing/Installing Air Filter (SEE FIGURE 7).
1. Remove air cleaner cover.
2. Remove the air lter.
3. Replace with new air lter.
4. Replace air lter cover.
SPARK PLUG
The recommended spark plug is a DK7RTC. The spark plug is
located to the left of the valve cover. SEE FIGURE 5
Checking And Changing Spark Plug
1. Check spark plug every 50 operating hours.
2. Disconnect the spark plug cap, and clean any debris from
around the spark plug area.
3. Remove spark plug and replace if any of the following occur;
pitted electrodes, burned electrodes, cracked porcelain, or
deposits around electrodes.
4. After analysis, seat spark plug and tighten with spark plug
wrench to compress the sealing washer.
• Reinstalloriginalsparkplug,tightenadditional1/2turn.
• Installingnewsparkplug,adjustsparkpluggapto.030”
(0.7-0.8 mm) and tighten additional 1/8 – 1/4 turn.
NOTE: Loose spark plug may overheat and damage engine.
Over tightened spark plug may damage threads in the
cylinder head.
Spark Plug Maintenance
Spark plug should be removed, cleaned and gap adjusted after
approximately fty hours of operating time.
NOTE: A sand blaster should not be used to clean spark plugs.
Microscopic particles remaining in the plug may score the
engine cylinder during operation. Use solvent and a wire brush
to clean the plug and compressed air to blow it out thoroughly.
CAUTION
NEVER RUN ENGINE WITHOUT AIR FILTER PROPERLY
INSTALLED. ADDED WEAR AND ENGINE FAILURE MAY
OCCUR IF AIR FILTER IS NOT INSTALLED ON ENGINE.
FIGURE 7
air cleaner base
air lter element
air cleaner cover