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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 16207
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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alpha 1 v6 4.3l mercruiser plugs have no spark turns over well

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alpha 1 v6 4.3l mercruiser plugs have no spark turns over well 12v every where.

Hello, and welcome to Justanswer. My name is XXXXX XXXXX I will be helping you today. If you need clarification on something please post back here.


Mercrusier uses quite a few ignition systems in these engines. I would need your engine serial number to see which ignition system you have.

Customer: replied 6 years ago.
thunderbolt iv ignition engine s/n od11097
Start by disconnecting the tachometer. Pull the tach out and disconnect the grey wire on the S terminal of it. Let me know if you get spark back or not.
Jason and other Boat Specialists are ready to help you
Customer: replied 6 years ago.
i have just done that and still no spark.

Then what you have is either a bad;

1. pickup in the distributor

2. ignition amplifier

3. ignition coil


To test it properly and not buy parts you don't need, you have to follow the troubleshooting flowchart. I have it here for you.


Just follow the chart step by step, without jumping around, and it will lead you to the problem.


Post back with questions.

Good luck!