Mercury MerCruiser Spark Plug AC 41-993 884019001 (Superseded to 8M0204739)
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Mercury MerCruiser Spark Plug — AC 41-993 / 884019001
| Field | Detail |
|---|---|
| Part Number | 884019001 / 33-884019001 |
| Original Plug | ACDelco AC 41-993 |
| Brand | Mercury Marine / MerCruiser |
| Official Product Type | Spark Plug — Platinum (OEM original service plug) |
| Supersedes | 41-932 / Mercury 884019 |
| Replaced By (Current) | Quicksilver 8M0204739 — NGK ITR4A-15 Laser Iridium |
| System | Ignition |
| Sold As | Individually (one plug per order unless specified) |
Engine Family & Compatible Applications
Originally specified for GM-based MerCruiser gasoline engines. Always confirm by engine serial number before ordering — similar engines can require different plug specs or gap settings.
- 4.3L MPI V6
- 5.0L MPI V8
- 5.7L / 350 MAG MPI V8
- 6.2L MPI V8
- 4.3L, 5.0L and 5.7L carbureted variants
- Scorpion 350
- Scorpion 377 HO
- 383 MAG Stroker (selected applications)
- Additional GM-based MerCruiser gasoline engines where the original parts catalog specifies 884019001
Serial Number & Gap Requirements
Confirm the engine model and MerCruiser serial number before ordering. The AC 41-993 was used with more than one gap specification depending on engine type:
- ~1.14 mm / 0.045 in. — selected carbureted applications
- ~1.52 mm / 0.060 in. — most MPI applications
Always follow the gap specification in the applicable Mercury service manual or engine owner's manual for your serial range. Do not assume one gap applies to all engines using this part number.
When to Replace Spark Plugs
- Worn, eroded, or fouled electrodes
- Heavy carbon, fuel, or oil deposits
- Corrosion on the shell or terminal
- Cracked or damaged ceramic insulator
- Difficult starting, rough idle, or intermittent misfire
- Reduced acceleration or engine performance
For multi-cylinder engines, replacing the complete set together helps maintain consistent ignition performance.
Service Interval
Mercury typically specifies spark plug inspection at each annual service and replacement every 200–300 hours of operation, or per the interval stated in your engine's owner's manual. Actual interval varies by engine type and use pattern.
Installation Notes
- Verify the plug specification and gap against the engine serial number and Mercury service information before installing
- Install into a cool cylinder head; follow Mercury's torque specification
- While servicing plugs, inspect spark-plug wires, boots, distributor (where equipped), and ignition coils for deterioration or corrosion
Alternate & Superseded Part Numbers
- 884019001 — original Mercury / MerCruiser number
- 33-884019001 — Mercury catalog format
- AC 41-993 — original ACDelco designation
- 41-932 — earlier ACDelco plug superseded by AC 41-993
- 884019 — earlier Mercury reference (AC 41-932 applications)
- 8M0204739 — current Mercury / Quicksilver replacement
- NGK ITR4A-15 — current replacement plug designation
Technical FAQ
Q: The replacement plug looks different from the one I removed — is that normal?
A: Yes. Mercury has moved this application to the Quicksilver 8M0204739 NGK ITR4A-15 Laser Iridium, which has a different appearance from the original AC 41-993 platinum plug. Focus on serial-number fitment, not visual match.
Q: Can I use the same gap as the plug I removed?
A: Not necessarily. Gap specification varies by engine model and serial range. Always verify against your Mercury service manual.
Q: Do I need to buy a full set?
A: This listing is sold individually. Order the quantity matching your engine's cylinder count. View the 8M0204739 4-pack if you need the current replacement in a multi-pack.
Related Parts
Parts Desk Insights
If your engine originally calls for 884019001 / AC 41-993, the most common customer question is whether the newer-looking 8M0204739 NGK Iridium is the right fit — it is, for most applications in this family, but always verify by serial number. Customers frequently order one plug when they need a full set; confirm cylinder count at the time of order. The gap setting is the other common issue — different applications within the same engine family use different gaps, so verify before installation rather than reusing the old plug's gap.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 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.