805570A2 Aftermarket Mercruiser Ignition Coil 8M0079202 | Sawley's Select Marine Parts

🔧 Product Description

Aftermarket replacement Thunderbolt Ignition Coil - Replaces Part Number: 805570A2

New aftermarket ignition coil replacing MerCruiser 805570A2 for Thunderbolt IV/V distributor systems. The current Mercury service reference is 8M0079202.

⚙️ Key Features

• Direct replacement for 805570A2

• Current replacement reference 8M0079202

• Thunderbolt IV/V ignition-coil characteristics

• Supports four-cylinder, V6 and V8 marine engines

• Marine epoxy-filled/high-voltage construction

🧰 Kit / Assembly Contents

• 1 × Ignition coil - Part Number: 805570A2

• Coil bracket, ballast components and high-tension lead are serviced separately unless supplied

🔄 Supersession & Cross Reference

OEM Supersession Chain:

• 8M0079202 → Supersedes 898253T24 and 805570A2

• 805570A2 → Supersedes/cross-references 805570A1, 802328, 392-7803A4, 7803A4 and 38547

OEM / Related Numbers:

• 8M0079202

• 898253T24

• 805570A1

• 802328

• 392-7803A4

• 7803A4

• 38547

Aftermarket / Verified Equivalents:

• Sierra: 18-5438

• MCC/Marine Power: 392-7803A4

• Recmar: REC805570A2

🚤 Compatibility

Commonly used on:

• MerCruiser Thunderbolt IV/V distributor ignition systems

Typically suits:

• Engine / Equipment models:

• 3.7L/470 family

• 4.3L V6

• 5.0L, 5.7L and 6.2L V8

• 7.4L and 8.2L big-block V8 where the listed Thunderbolt coil is specified

• HP / Output Range: Approximately 165HP - 500HP

• Engine / System Type: GM petrol marine engine with Thunderbolt distributor ignition

• Year Range: Model- and engine-serial dependent

• Serial / Component Identification: Confirm Thunderbolt ignition and coil primary resistance; ECM555 MPI uses a different coil.

🔌 Function

The ignition coil converts battery voltage into the high voltage required to fire the spark plugs. The engine-control or ignition module switches the coil primary circuit to produce a timed spark.

Common signs of failure / service requirement:

• Crank/no-start with weak or absent spark

• Misfire that worsens as the engine or coil heats up

• Rough idle, hesitation or loss of power

• Cracked housing, corrosion or high-voltage leakage

• Incorrect primary or secondary resistance and repeated ignition-module faults

📦 Condition

• New aftermarket replacement part

• Brand new

• Supplied in original or equivalent packaging