Mercury 300 Verado - Spark Plug Inspection and Replacement

MAINTENANCE
70
Description Nm lb. in. lb. ft.
Propeller nut 75 55
8. Secure propeller nut by bending three of the tabs into the thrust hub grooves.
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Spark Plug Inspection and Replacement
1. Remove top and rear cowlings. Refer to Cowl Removal and Installation.
2. Disconnect the six wiring harness connectors from pencil coil connections.
3. Remove mounting bolts, using a twisting motion, and pull pencil coils from spark plugs.
a
b
c
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a - Wiring harness connector
b - Pencil coil
c - Bolt
4. Remove the spark plugs to inspect. Replace spark plug if electrode is worn, threads of seal area
are corroded, or the insulator is rough, cracked, broken, blistered or fouled.
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5. Set the spark plug gap to specifications.
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Spark Plug
Spark Plug Gap 0.8 mm (0.0315 in.)
6. Saltwater use - Apply a thin coating of Anti-Seize Compound only on threads of spark plugs.