How to correctly choose and maintain marine spark plugs? An article will give you an in-depth understanding

1. Characteristics of marine spark plugs

• Stronger corrosion resistance

Due to the long-term humid and high-salt environment of ships, ordinary spark plugs are prone to rust or corrosion. Marine spark plugs usually use stainless steel shells or special coatings (such as nickel-chromium alloys) to improve corrosion resistance.

• Higher heat resistance

Marine engines (especially outboards) often need to operate at high loads for a long time, and spark plugs must be able to withstand higher temperatures. Therefore, the electrode materials (such as iridium or platinum) and insulators of marine spark plugs are more heat-resistant than ordinary spark plugs.

• Optimized waterproof design

Marine spark plugs have better sealing to prevent moisture from entering the ignition system. Some high-end models also use silicone seals or double-layer ceramic insulators to cope with wave splashing and humid environments.

• Adapt to different fuel types

Gasoline outboard motors: Use spark plugs similar to those used in cars, but with higher corrosion resistance.

Liquefied petroleum gas (LPG) or natural gas engines: require specially designed spark plugs to adapt to different combustion characteristics.

2. How to choose the right marine spark plug?

Choose according to engine type

Two-stroke outboard motor: usually use spark plugs with higher calorific value

Four-stroke marine engine: may need long-life iridium spark plugs

Pay attention to calorific value matching

Too high calorific value: the spark plug dissipates heat too quickly, which can easily lead to carbon deposits.

Too low calorific value: the spark plug overheats, which may cause pre-ignition or electrode ablation.

Material selection

3. Common faults and solutions for marine spark plugs

Spark plug carbon deposits

Phenomenon: difficult starting, weak acceleration, unstable idling speed.

Cause: long-term low-speed sailing, poor fuel quality, too rich mixture.

Solution: remove the spark plug, soak it in carburetor cleaner and then brush it. Adjust the fuel mixture ratio (pay attention to the oil ratio for two-stroke engines). Regularly run at high speed (such as running at full throttle for a few minutes) to help burn carbon deposits.

Electrode ablation

Phenomenon: engine cylinder shortage and power reduction.

Cause: spark plug heat value is too low, ignition time is too early, long-term overload operation.

Solution: replace spark plugs with higher heat value and check ignition timing.

Insulator rupture

Phenomenon: engine shaking and ignition failure.

Cause: mechanical impact (such as over-tightening during installation), thermal shock (rapid cooling).

Solution: replace new spark plugs and install them according to standard force using a torque wrench.

Salt spray corrosion

Phenomenon: Spark plug thread rust, poor contact.

Solution: Regularly disassemble and inspect, apply anti-rust lubricant (such as copper-based anti-seizure paste), and choose stainless steel spark plugs.