Black wire coming out of bottom of Thunderbolt distributor - where does it go?

[Cptkid570]

1985 Mercruiser 5.7 liter/260 horsepower. Thunderbolt ignition.

I'm not getting spark. I don't know if this is the problem, but in looking around the distributor, I found that there are 3 wires that come out of it. 2 that I believe go to the coil and 1 single black wire that looks like it comes directly out of the back, bottom of the distributor. Where does this wire go? I looked at wiring diagrams and my best guess would be the ignition module that is mounted on the risor. Is this correct? I did find a loose and rusty bolt on it. If this is where it goes, the block wire goes to this screw and then there is another black wire that goes from this screw into the ignition module.

I've attached pics.

Also, would this prevent the engine from firing? Since the wire is black, I did connect it directly to the negative on the battery, and still no spark, but maybe it has to mount to the ignition module for there to be spark?

thank you for your help.

 

[Cptkid570]

Re: Black wire coming out of bottom of Thunderbolt distributor - where does it go?

The black wire that you see in the ignition moldule (first pic) only goes from that rusty bolt into the ignition module (if that thing on the risor is, in fact, the ignition module.

 

[achris]

Re: Black wire coming out of bottom of Thunderbolt distributor - where does it go?

The black from under the dissy needs to get bolted to a good ground on the engine block. The black wire on the ignition module looks terrible. Check that it's actually grounding properly...

 

[Cptkid570]

Re: Black wire coming out of bottom of Thunderbolt distributor - where does it go?

well, that rusty bolt on the ignition module actually came out. That is why I think that the wire from the distributor may go to it, but it doesn't really fit around the rusty bolt very well, so I wanted to make sure. Either way, I will be replacing the rusty bolt.

 

[Cptkid570]

Re: Black wire coming out of bottom of Thunderbolt distributor - where does it go?

If that ground wire on the riser for the ignition module does come loose, can it cause the engine to not fire?

 

[achris]

Re: Black wire coming out of bottom of Thunderbolt distributor - where does it go?

If that ground wire on the riser for the ignition module does come loose, can it cause the engine to not fire?

Most definitely...

 

[Cptkid570]

Re: Black wire coming out of bottom of Thunderbolt distributor - where does it go?

Yep! I re-attached the wires with a new bolt and the engine fired up. so, that was it. It must've finished wiggling loose when I pulled the engine. I'm very relieved because I don't know electrical very well. The wiring diagram came in very handy.

Thank you!