TB IV Ignition module replacement

[Viddi]

1992 Merc 5.0L V8
I need to replace my ignition module, but I am not sure what I need. I found what I thought to be my serial (based on the manuals description of where the serial plate is) but it doesn't seem to match the typical format 10243878.

As far as I can tell, the part number I need is 15899T01, but when the dealer looked it up, he said it was no longer available. I have found a module online, but he does not have a part number. The picture looks the same, but it may be much different than what I need? Here is the info on the one he posted:

You are bidding on a NEW (Not in BOX)

Mercruiser Ignition Module
Thunderbolt IV
V8
The number on the front reads: 4C17A V8-24
on the back reads: 4C11AA
The connector has 6 prongs

I noticed on my existing that mine says v8-22 does that mena the V8-24 listed above will not work?

Attached are pictures of the one I currrently have installed, and the one for sale.

Has anybody replaced one of these? It looks like it is riveted onto the plate...do you just drill out the rivets?

 

[Bondo]

Re: TB IV Ignition module replacement

Ayuh,...

You need 1 stamped V8-22,... V8-24 is hotter timing for a different motor....

 

[Viddi]

Re: TB IV Ignition module replacement

Thanks for the heads up about the timing. Any idea of the part number I need...or where I can find one (preferably for a good price)

 

[JustJason]

Re: TB IV Ignition module replacement

uhmmm.... you most certainly should be able to get one from a dealer.
Unless of course your not happy with the price, they're not a cheap module.

That part has had a couple of redesigns, and part numbers get superceeded all the time. Some parts guys are not and brightest, and don't know how do look up supercessions. Instead of giving the guy the part number, give him your engine serial and have him look up the actual part.
Hope your right, that's an expensive part to guess at. And they don't go bad to often.
Just for giggles. Cut the end of the ground leads coming out of the box, put new ends on it and clean up the mounting grounds and try it again.

 

[achris]

Re: TB IV Ignition module replacement

The ignition module comes with the plate... Your module is mounted to the side of the port exhaust elbow.. The one on e-bay was mounted to the distributor... Different animals....

The correct part number for your engine, as per the Merc parts CD, is the one you gave, -15899T01. They are available from Mercury, still a current part... But they are expensive, $350+... Try one of the on-line sellers... I use mercruiserparts.com... They have them for $316.53

The numbers on it, 'V8-22', indicate that it is for a V8 (duh!) and has a maximum advance of 22 degrees... (The advance curve itself may also be different)

HTH

Chris..............

 

[wca_tim]

Re: TB IV Ignition module replacement

the v8-24 starts to come in just a couple hundred rpms earlier and reaches full advance earlier (24 at 3500 vs 22 @ 4500). It's enough hotter that it could cause detonation especially under heavy load in the 2500-3500 range where there is a 4 or 5 degree difference.. I would find or just order the right one...