Mercury Spark Plug QL77JC4 896329828
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
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
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Genuine Mercury Marine OEM spark plug
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Champion QL77JC4 marine spark plug design
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Copper core electrode for improved conductivity and heat transfer
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Resistor design helps reduce radio frequency interference (RFI)
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Corrosion-resistant shell for marine environments
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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
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Mercury 7.5HP – 25HP two-stroke outboards (various models)
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Select Mercury SportJet engines
MerCruiser Engines
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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:
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Improve engine starting reliability
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Restore proper ignition performance
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Prevent engine misfires
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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
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33-896329828 – Mercury service reference number
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33-828S – Earlier Mercury equivalent
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Champion 828M / QL77JC4 – Manufacturer reference
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NGK BZ7HS-10 / BR9HS – Common cross-reference equivalents
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.