AC Delco MR43T Iridium Spark Plug - Cross-Reference Mercury 33-8M0204752, NGK BR6FS

The AC Delco MR43T is an iridium spark plug built for outstanding strength and high-temperature resistance. It uses a nickel alloy tip paired with a copper core, a combination chosen to maximize heat transfer while the iridium electrode construction holds up to sustained high melting-point conditions. A ribbed suppressor seal is fitted to support durability and consistent performance over the plug's service life.

Because the electrode is laser-welded, the MR43T is designed to deliver reliable cold starting along with quick acceleration and smooth engine performance once the engine is running. It is a genuine AC Delco part rather than a generic aftermarket substitute, and it cross-references to plug numbers used across several other brands, making it a straightforward replacement option for engines originally fitted with the equivalent Mercury, Donovon, or NGK plug.

Specifications

• Brand: AC Delco
• Manufacturer Part Number: ACDEMR43T
• Product Type: Spark Plug
• Electrode Construction: Iridium
• Tip Material: Nickel alloy
• Core Material: Copper
• Seal: Ribbed suppressor seal
• UPC: 808709617204
• Weight: 0.1 pounds

Fitment

No specific make, horsepower, or model fitment is listed for this part; it is cross-referenced by plug equivalence.

Replaces (OEM)

• Mercury 33-8M0204752
• Donovon 203276
• NGK BR6FS

Frequently Asked Questions

What does the AC Delco MR43T spark plug cross-reference to? The MR43T cross-references to Mercury 33-8M0204752, Donovon 203276, and NGK BR6FS, so any engine specifying one of those plug numbers can use the AC Delco MR43T instead.

Is the MR43T an iridium spark plug? Yes, the AC Delco MR43T uses iridium electrode construction, which is built for a high melting point and outstanding strength and heat resistance.

What is the MR43T's electrode tip made of? The AC Delco MR43T has a nickel alloy tip combined with a copper core, a pairing intended to support heat transfer and plug durability.

Does the MR43T work as a replacement for an NGK BR6FS plug? Yes, NGK BR6FS is listed as a direct cross-reference for the AC Delco MR43T.

How much does the AC Delco MR43T weigh? The AC Delco MR43T weighs 0.1 pounds.

What is the UPC for the AC Delco MR43T spark plug? The UPC for the AC Delco MR43T is 808709617204.

Will the MR43T help with cold starting? Reliable cold starting is one of the stated benefits of the AC Delco MR43T's iridium construction, along with quick acceleration and smooth engine performance.

What kind of seal does the MR43T use? The AC Delco MR43T is fitted with a ribbed suppressor seal for durability and performance.

Is the AC Delco MR43T a genuine AC Delco part or an aftermarket copy? The MR43T is a genuine AC Delco iridium spark plug, not a generic aftermarket substitute.

What Mercury part number does the AC Delco MR43T replace? The AC Delco MR43T cross-references to Mercury part number 33-8M0204752.

Why is the electrode laser-welded on the MR43T? The AC Delco MR43T's electrode is laser-welded as part of its iridium construction, supporting durability alongside its high melting point rating.