Description

Restore proper ignition performance and reliable engine starting with the Mercury Spark Plug QL77JC4 – 896329828. This genuine Mercury Marine OEM spark plug is designed for use in many Mercury and MerCruiser engines, providing consistent spark and reliable combustion in marine environments.

The QL77JC4 plug features a copper core center electrode and resistor design that helps improve conductivity and reduce radio frequency interference (RFI) that can affect onboard electronics. Marine-grade construction provides excellent corrosion resistance and reliable operation even under heavy engine loads.

Key Features

• Genuine Mercury Marine OEM spark plug

• Champion QL77JC4 marine spark plug design

• Copper core electrode for improved conductivity and heat transfer

• Resistor design helps reduce radio frequency interference (RFI)

• Corrosion-resistant shell for marine environments

• Provides reliable ignition and smooth engine operation

Part Details

OEM Part Number: 896329828
Mercury Reference Number: 33-896329828
Champion Plug Number: QL77JC4 / 828M
Product Type: Marine engine spark plug

Thread Size: 14 mm
Reach: 0.500 in
Seat Type: Flat seat
Hex Size: 20 mm

Typical Packaging: Individual spark plug

Compatible Mercury & MerCruiser Engines

Commonly used on various Mercury and MerCruiser applications including:

Mercury Outboards

• Mercury 7.5HP – 25HP two-stroke outboards (various models)

• Select Mercury SportJet engines

MerCruiser Engines

• Select SportJet and small gasoline marine engines

This spark plug is also used in various Johnson, Evinrude, and Yamaha marine engines, depending on model and ignition specifications.

Function

Spark plugs ignite the compressed air-fuel mixture inside the engine cylinder, allowing the engine to produce power. Proper spark plug performance is critical for smooth operation and efficient combustion.

Replacing worn spark plugs helps:

• Improve engine starting reliability

• Restore proper ignition performance

• Prevent engine misfires

• Maintain fuel efficiency and engine power

Important Compatibility Note

Spark plugs vary depending on engine model, ignition system, and production year. Always verify compatibility using the engine serial number or owner’s manual before ordering to ensure the correct spark plug specification.

Cross-Stock / Superseded Part Numbers

• 33-896329828 – Mercury service reference number

• 33-828S – Earlier Mercury equivalent

• Champion 828M / QL77JC4 – Manufacturer reference

• NGK BZ7HS-10 / BR9HS – Common cross-reference equivalents

Shipping: Ships same or next day for fast Canada wide shipping.