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Mercruiser Thunderbolt Ignition Components

We have Thunderbolt tune-up kits for every
Mercruiser Sterndrive and Inboard Engine made.

Here are a few simple tune-up tips.
1. Check for deposit build-up inside your distributor cap.
2. Always replace the sensor wheel along with the rotor.
3. Make a note of your firing order BEFORE the tune-up.
5. Make sure you have the correct engine specifications.
6. Use White Out to mark your harmonic damper timing line.
7. Use care installing a ThunderBolt Sensor wheel! Don't bend any tabs.
8. Never over-tighten the sensor unit mounting screws.
9. Make sure your distributor ground wire is properly fastened.
10. Use only Mercruiser spark plug wires.

Thunderbolt Information

How do you know if you have a Thunderbolt Ignition System?
There are a few differnt ways to indentify which type of ignition system you have.
One of the simplest methods is to look at the cap.

The Cap and Rotor Kit shown above is part 815407T5 for $36.00 This fits all Mercruiser V6 engines with the Thunderbolt Ignition System.

The Cap and Rotor Kit shown above is part 805759T3 for $45.00 This fits all Mercruiser V8 engines with the Thunderbolt Ignition System.

If you remove the cap you can see the Thunderbolt IV or Thunderbolt V sensor unit.
The sensor is underneath the rotor and sensor wheel assembly.
V6 rotor/sensor wheel assemblies are NOT THE SAME as the V8 rotor sensor wheel assemblies.

V6 Rotor/Sensor Wheel Assembly Part 13524A6 for $14.00

V8 Rotor/Sensor Wheel assembly Part 13524T1 for $14.00

The Thunderbolt IV and Thunderbolt V systems have similiar Caps, rotors and sensors.
Earlier Thunderbolt IV sensors uses brass nuts for attaching the harness wires
Newer Thunderbolt IV and Thunderbolt V sensors used bullet connectors.
Replacement Sensors have pigtails for either type of connection.

Thunderbolt IV with nuts. Part 87-892150K02 Sensor for $94.00

Follow your engine manuals procedures for replacing any and all ignition components.
Special care must be taken not to bend the sensor wheel tabs during installation.
The rotor fits very tightly on the distributor shaft which makes removal and installation difficult.
Use a soft piece of wood on top of the rotor and a soft mallat to tap it down into place.

Thunderbolt Tune-Up Kits

The BEST way to order the correct Tune-Up Kit is to email us.
Include your engine type and serial number.

Keep an eye out as we will be expanding this area a LOT!

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