Part Number: 603-MR43T
AC Delco MR43T Spark Plug
Keep your marine engine running smoothly with the AC Delco MR43T Spark Plug. Designed for dependable ignition performance in GM-based inboard marine engines, this OEM-quality spark plug delivers consistent spark energy for efficient combustion, reliable starting, smooth idle characteristics, and strong throttle response.
Marine engines operate in demanding environments where moisture, heat, and extended periods of operation can accelerate wear on ignition components. A fresh set of spark plugs is one of the simplest and most effective ways to maintain peak engine performance, improve fuel efficiency, and reduce the likelihood of misfires or hard-starting conditions.
Manufactured to AC Delco's exacting standards, the MR43T spark plug is engineered for long service life and reliable operation in marine applications. Whether you're performing routine maintenance or a complete ignition tune-up, this spark plug helps restore factory-level performance and dependability.
Common Engine Applications
The AC Delco MR43T spark plug is commonly used in GM-based marine engines, including:
- Indmar 5.7L MPI
- Indmar Assault 310
- Indmar Assault 325
- Indmar Monsoon 320
- Indmar Monsoon 325
- MerCruiser 5.0L V8
- MerCruiser 5.7L V8
- MerCruiser 260
- PCM Excalibur 5.7L
- Volvo Penta 5.7Gi
- Crusader 5.7L MPI
Common Inboard Boat Fitments
These engines are frequently found in popular inboard ski, wake, and surf boats, including:
Supra
- Supra Launch 20SSV
- Supra Launch 21V
- Supra 22SSV
- Supra Sunsport 22V
- Supra Comp
Moomba
- Moomba Mobius LSV
- Moomba Mobius XLV
- Moomba Outback
- Moomba Mojo
- Moomba Mobius LS
Malibu
- Malibu Wakesetter VLX
- Malibu Wakesetter 23 LSV
- Malibu Response LX
- Malibu Sunsetter LXi
MasterCraft
- MasterCraft X-2
- MasterCraft X-15
- MasterCraft X-Star
- MasterCraft ProStar 197
Nautique
- Ski Nautique 196
- Super Air Nautique 210
- Super Air Nautique 220
- Nautique 216
Additional applications may include Centurion, Sanger, Calabria, and other boats equipped with compatible GM-based marine engines.
Features
- Genuine AC Delco OEM-quality spark plug
- Designed for GM-based marine engines
- Provides consistent spark for efficient combustion
- Helps improve starting performance and throttle response
- Resistant to fouling in marine operating conditions
- Ideal for routine tune-ups and preventative maintenance
- Supports smooth idle and reliable engine operation
Why Replace Spark Plugs?
Over time, spark plugs wear and can lose their ability to ignite the air-fuel mixture efficiently. Replacing them at recommended service intervals helps maintain engine performance, fuel economy, and overall reliability while reducing the risk of ignition-related issues.
Whether you're maintaining a Supra, Moomba, Malibu, MasterCraft, Nautique, or another inboard boat powered by a GM-based marine engine, the AC Delco MR43T Spark Plug provides the dependable ignition performance needed to keep your boat performing at its best all season long.