question for a friend - 1989 4.3 Mercruiser V6 175hp Thunderbolt Ignition No Spark

[wan2live]

Recently replaced coil due to no spark boat ran for 3min and cut off and will not to start again, it turns over just will not engage to start. Checked for spark from coil, no spark again.

What is the correct wiring of coil? Currently both purple wires are to + and both gray wires are to -.

Is this a symptom of bad ignition module?

 

[wire2]

Re: question for a friend - 1989 4.3 Mercruiser V6 175hp Thunderbolt Ignition No Spar

With key "ON", do you have 12 v on + coil terminal to engine ground?

If yes, place a small 12 lamp across + and - of coil with aligator leads.

Does it flicker when you crank?

If not, no pulses coming from module.

 

[Chris1956]

Re: question for a friend - 1989 4.3 Mercruiser V6 175hp Thunderbolt Ignition No Spar

Wan, There is several parts to the ignition system on that motor. There is a simple troubleshooting procedure in the MerCruiser manual, which will identify the exact bad part.

I bought a Clymer manual ($25), and it seemed adequate for my purposes. I recommend your friend pick up some kind of a manual. You might google "Thunderbolt Ignition troubleshooting", and see if you get some hits. there is quite a bit of info on the web for free.

The only problem I ever had with the ignition system on my '88 Mercruiser 4.3LX is that the Ign module inside the distributor failed one Saturday in October. To replace the module I needed to pull the dissy and remove the rotor shaft. I then had to reinstall and retime the bloody thing. I haven't had to do that kind of work since high school auto shop! Took a few beers to remember how!

 

[Haut Medoc]

Re: question for a friend - 1989 4.3 Mercruiser V6 175hp Thunderbolt Ignition No Spar

This should help you track down the problem.

 

[Haut Medoc]

Re: question for a friend - 1989 4.3 Mercruiser V6 175hp Thunderbolt Ignition No Spar

Whoops, that was Don's post for TB V.....
What is your system TB IV or V.......​

 

[wan2live]

Re: question for a friend - 1989 4.3 Mercruiser V6 175hp Thunderbolt Ignition No Spar

Thanks for the information fella's I will pass it on, thanks for the diagram I think he has a V

 

[wan2live]

Re: question for a friend - 1989 4.3 Mercruiser V6 175hp Thunderbolt Ignition No Spar

Ok all tests completed it looks like the ignition module is what has went bad on him. He will be ordering or picking up another one tomorrow.

 

[1988invadar]

Re: question for a friend - 1989 4.3 Mercruiser V6 175hp Thunderbolt Ignition No Spar

Hi

Just had this same situation

The ignition sensor was the problem after 20 years of use replaced all ignition parts

make sure you test it first before spending big bucks on the Module.


runs like a champ.