Does anyone know what controls the ignition curve is it controlled by the ignition module or the spark control module and what do these modules control , do you need both of them to run the system. I have a voyager distributor which I would like to upgrade but not sure what is needed . I would like to stay with a mercruiser system . any suggestions. Thanks

The ignition module controls the curve. The spark module is your rev limiter.

TBIV and TBV ( on the carb engines) have a external
ignition module that controls the advance.

The EFI's use a GM HEI type of distributors,
and the ECM is in control of the timing.

I already told you exactly what you needed, found you the parts in the swap shop, and told you to reply to the ad in the thread or upgrade your membership so you could send a PM to the person that placed the ad.
http://www.offshoreonly.com/forums/s...d.php?t=172995

What more do you want???

griff you need to chill out
I'm looking for information of these modules seeing mercruiser uses some many different types.

We use that type of distributors in
some of the forklifts we sell.

On the older units, timing was controlled by
the ignition module in the distributor,
it had about 22* max advance.

The newer units have an external timing module
that takes inputs from various sensors, and
timing is determined by the external module.

It interfaces to the distributor through the 4 pin
connector on the module.

Both units use the same distributor.

I don't know if the module merc uses
is capeable of advance though.

Take it to a auto electric repair shop, have
them put it on a distributor machine and
see what/ if it has for advance.

Sorry, I guess that was a little harsh. If you wanted more detailed info you should have asked specific questions in the other thread.
This is all information about Thunderbolt IV ignitions and the info does not apply to the TB V's.
The ignition module controls the advance curve. They are stamped with various markings V8-HP, V8-22, V6-14, V8-24, etc. The merc part number won't show this. Each module has different curve and full advance will occur at different rpms depending on the module used. The ign modules do not have a built in rev limiter. None of the standard black Merc engines used a rev limiter. The spark control module you refered to is Merc's version of a rev limiter. It was used on Merc Racing/blue engines.
A Crane Marine box has about 6 Merc curves built into the box and you can choose which one you want to use with the turn of a dial. The box also has a built in rev limiter that you can adjust to your engine specs. It will work with a TB IV distributor.

Here are the charts for the curves and the part numbers and the curve for the delco voyager. Ignore the red markings. The V8-HP is no longer in production.

Here is another chart of the curves.

http://www.mtboats.com/mercuryigniti...cemodules.html

Griff, Just to addd to your info.

Sorry guys. I should have looked at all the post.

Does anyone have a part# for the Module for the GM Voyager Ignition System V8 application. There are part numbers for every other part in the Manual that came with the Voyager Kit. No number for the Module?