ACDelco 411104 Iridium Spark Plug — 4-Pack | GM Marine Engines
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
ACDelco Iridium Professional Spark Plugs for GM-Based Marine Engines
The ACDelco 411104 Iridium Professional spark plug delivers long-life, high-efficiency ignition performance for GM-based marine engines. The fine-wire iridium electrode produces a more focused spark for improved combustion efficiency, smoother idle, and quicker throttle response. Sold as a 4-pack.
Note: The 411104 is a distinct part number from the ACDelco 411014 and covers different GM marine engine configurations. Always verify the correct plug number for your specific engine before ordering.
Compatible Applications
- GM-based marine engines requiring ACDelco 411104 iridium spark plug
- MerCruiser, Crusader, and Indmar engines using GM V8 blocks — verify OEM plug number before ordering
Key Features
- Fine-wire iridium center electrode for precise, consistent spark
- Reduced ignition system voltage demand — extends the life of coils, wires, and ignition components
- Improved cold-start performance and throttle response
- Long-life design for extended service intervals
- Sold as a 4-pack (standard pack)
Parts Desk Insights
The ACDelco 411104 is the iridium upgrade plug for GM V8-based marine engines — but it is a different heat range specification than the 411014. Using the wrong heat range on a marine engine can cause fouling or pre-ignition, so always confirm your engine’s OEM spark plug number before selecting between the 411014 and 411104. On the water, iridium plugs are worth the upgrade over standard copper plugs because the lower voltage demand reduces wear on ignition coils and wires — components that are more expensive and harder to service in a marine environment. Pair with a quality spark plug wire set for a complete ignition tune-up, such as the Sierra Marine Spark Plug Wire Set.
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.