The Prime Guard ACDEMR43T is a specialty marine spark plug (cross-reference: ACDelco MR43T) engineered for reliable ignition performance in marine applications. Designed as an everyday replacement plug, it delivers dependable performance in jet boats, inboards, outboards, and personal watercraft.
Built with a high-quality copper core, this plug offers excellent heat transfer and stable operating temperatures across varying engine loads — critical for demanding marine environments. The long-reach design makes it compatible with pre-Vortec carbureted marine engines including 3.0L, 4.3L, 5.0L, 5.7L, and 6.2L displacements.
Key Features:
- Copper core for superior heat transfer and enhanced plug durability
- Ribbed suppressor seal reduces resistance and helps prevent spark flash-over and misfires
- Nickel-chrome alloy sheathing on center electrode for corrosion resistance
- Nickel alloy center electrode tip with pre-gapped at 0.040 in.
- Resistor-type construction for reduced electromagnetic interference
- Long-reach design suited for pre-Vortec marine engines
Specifications:
- Part Number: ACDEMR43T / MR43T
- GM Part Number: 5613438
- Center Electrode Tip Material: Nickel Alloy
- Ground Electrode Tip Material: Nickel
- Resistor: Yes
- Pre-Gap Size: 0.040 in.
Cross-Reference / Replaces:
- NGK: BR6FS, B6FS, BR6FS-15, YR5, YR55
- Champion: RV8C, RV8C6, RBL8, BL8, BL9Y, RV12C6
- Mercury/Mercruiser: 33-898264001
- OMC: 0763819
This plug is a direct-fit replacement for a wide variety of marine engines, making it an ideal choice for tournament ski boats, wakeboard boats, jet boats, and other marine powerplants requiring a reliable, heat-stable spark plug.
