3. Neglecting to Change Spark Plugs
What It Does: Spark plugs ignite the fuelair mixture in the fuel when they’re clean, properly gapped and serviceable.
Result Of Neglect: Spark-plug contacts (electrodes) erode over time — especially in outboards. As the gap widens with use, the spark plug fails to ignite the fuel-air mix, resulting in fouling. Fuel economy and performance suffer first, but if a bad plug remains, sooting can destroy the engine.
Cost To Perform: Spark plugs for a V-6 outboard can cost $10 each and up. Changing them requires only a socket wrench and 40 minutes.
Penalty: An outboard power head can cost $6,000 to $10,000.