Carburetor Adjustment; Spark Plug Inspection - Yamaha EF4000DFW Owner's Manual

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Carburetor adjustment

The carburetor is a vital part of the engine. Adjusting
should be left to a Yamaha dealer with the professional
knowledge, specialized data, and equipment to do so
properly.

Spark plug inspection

The spark plug is important engine components, which
should be checked periodically.
1. Remove the spark plug cap and the spark plug.
1
1 Spark plug cap
2 Spark plug
2. Check for discoloration and remove the carbon.
The porcelain insulator around the center elec-
trode of spark plug should be a medium-to-light
tan color.
3. Check the spark plug type and gap.
Standard spark plug:
BPR4ES (NGK)
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
a Spark plug gap
760-001a
TIP
The spark plug gap should be measured with a wire
thickness gauge and, if necessary, adjusted to specifi-
cation.
4. Install the spark plug.
Spark plug tightening torque:
20 Nm (2.0 m·kgf, 14 ft·lbf)
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