Below are the ignition coils currently available from AA Ignition. We are constantly adding more ignition coils to our catalog so check back for new products.

Replacement Inboard Ignition Coil - Fits MerCruiser Thunderbolt IV & V Ignition Systems with HEI - Replaces# Sierra 18-5438

Replacement Inboard Ignition Coil - Fits MerCruiser Thunderbolt IV & V Ignition Systems with HEI - Replaces# Sierra 18-5438 Image
  • REPLACEMENT INBOARD MARINE ENGINE IGNITION COIL – The ignition coils or ignition coil plug provides spark for your engine. Over time the factory ignition coil packs can fail leading to hard starting or losing power when the engine is hot or your boat may run erratically. Replace your faulty ignition coil and restore performance and driveability on your boat.
  • FITS V6, V8 308 & 350 ENGINES WITH THUNDERBOLT IV & V IGNITION SYSTEM – Only works with HEI (High Energy Ignition) Systems and will not work with Point Ignition Systems. This replacement ignition coil by AA Ignition made by an original equipment supplier will get your 4.3L, 5.0L, 5.7L, 6.2L, 7.4L & 8.2L Mercruiser GM petrol engines with Thunderbolt 4 and 5 ignition systems.
  • REPLACES PART# Sierra 18-5438, Mercury 392-805570A2, 392-7803A4, 392-805570A1, GLM 72115, PerTronix 40511, Mallory 9-29701, Pro Marine 64570, RL5438. The ignition coil of your boat can easily be located beside the distributor which is found in the engine.
  • OEM FIT, QUALITY, FINISH – While this is not a genuine MerCruiser, Sierra, PerTronix, Mercury, GLM or OMC part, it is a direct replacement for your OMC Cobra Sterndrive boat or MerCruiser boat engine and it will appear, fit and work like the factory part. Save time and hundreds of dollars off of dealer prices by replacing the part yourself.
  • 2 YEAR OR 24,000 MILE WARRANTY – This ignition coil pack comes complete with a 2 year or 24, 000 mile warranty. If the coil ever fails on your boat within the warranty period, simply contact us for a replacement. Save time and money by taking advantage of this warranty.

If your boat won’t run at full power or is hard to start then a faulty ignition coil may likely be the cause. This replacement ignition coil by AA Ignition made by an original equipment supplier installs quickly and will bring your boat motor back up to full power. Installation is straight forward and will restore performance and driveability on your boat in minutes

Replaces the following part numbers:

  • Sierra 18-5438
  • Mercury 392-805570A2, 392-7803A4, 392-7803, 3000-8M0079202, 392-805570A1
  • GLM 72115
  • PerTronix 40511
  • Mallory 9-29701
  • Pro Marine 64570
  • Redline RL5438

Fits Mercruiser GM V‑6 & V‑8 petrol engines w/ Thunderbolt IV & V ignition:

  • 4.3L V6
  • 5.0L V8
  • 5.7L V8 (Inc 350 MAG)
  • MX6.2L V8
  • 7.4L V8 (Inc 454 MAG)
  • 8.2L V8 (Inc 502 MAG)

This is a compatible replacement part manufactured by AA Ignition. This ignition coil pack is NOT a genuine MerCruiser, Sierra, OMC, Mercury, PerTronix, Mallory, Pro Marine or Redline part. Their associated models and part numbers are used in this listing only to identify the vehicles this ignition coil pack fits.

Replacement Inboard Ignition Coil - Fits MerCruiser Thunderbolt IV & V Ignition Systems with HEI - Replaces# Sierra 18-5438

Replacement Inboard Ignition Coil - Fits MerCruiser Thunderbolt IV & V Ignition Systems with HEI - Replaces# Sierra 18-5438 Image
  • REPLACEMENT INBOARD MARINE ENGINE IGNITION COIL – The ignition coils or ignition coil plug provides spark for your engine. Over time the factory ignition coil packs can fail leading to hard starting or losing power when the engine is hot or your boat may run erratically. Replace your faulty ignition coil and restore performance and driveability on your boat.
  • FITS V6, V8 308 & 350 ENGINES WITH THUNDERBOLT IV & V IGNITION SYSTEM – Only works with HEI (High Energy Ignition) Systems and will not work with Point Ignition Systems. This replacement ignition coil by AA Ignition made by an original equipment supplier will get your 4.3L, 5.0L, 5.7L, 6.2L, 7.4L & 8.2L Mercruiser GM petrol engines with Thunderbolt 4 and 5 ignition systems.
  • REPLACES PART# Sierra 18-5438, Mercury 392-805570A2, 392-7803A4, 392-805570A1, GLM 72115, PerTronix 40511, Mallory 9-29701, Pro Marine 64570, RL5438. The ignition coil of your boat can easily be located beside the distributor which is found in the engine.
  • OEM FIT, QUALITY, FINISH – While this is not a genuine MerCruiser, Sierra, PerTronix, Mercury, GLM or OMC part, it is a direct replacement for your OMC Cobra Sterndrive boat or MerCruiser boat engine and it will appear, fit and work like the factory part. Save time and hundreds of dollars off of dealer prices by replacing the part yourself.
  • 2 YEAR OR 24,000 MILE WARRANTY – This ignition coil pack comes complete with a 2 year or 24, 000 mile warranty. If the coil ever fails on your boat within the warranty period, simply contact us for a replacement. Save time and money by taking advantage of this warranty.

If your boat won’t run at full power or is hard to start then a faulty ignition coil may likely be the cause. This replacement ignition coil by AA Ignition made by an original equipment supplier installs quickly and will bring your boat motor back up to full power. Installation is straight forward and will restore performance and driveability on your boat in minutes

Replaces the following part numbers:

  • Sierra 18-5438
  • Mercury 392-805570A2, 392-7803A4, 392-7803, 3000-8M0079202, 392-805570A1
  • GLM 72115
  • PerTronix 40511
  • Mallory 9-29701
  • Pro Marine 64570
  • Redline RL5438

Fits Mercruiser GM V‑6 & V‑8 petrol engines w/ Thunderbolt IV & V ignition:

  • 4.3L V6
  • 5.0L V8
  • 5.7L V8 (Inc 350 MAG)
  • MX6.2L V8
  • 7.4L V8 (Inc 454 MAG)
  • 8.2L V8 (Inc 502 MAG)

This is a compatible replacement part manufactured by AA Ignition. This ignition coil pack is NOT a genuine MerCruiser, Sierra, OMC, Mercury, PerTronix, Mallory, Pro Marine or Redline part. Their associated models and part numbers are used in this listing only to identify the vehicles this ignition coil pack fits.