Thunderbolt IV replacement Module

[Jaegerboy]

Can anyone tell me the replacement amplifier for this Thunderbolt IV (See pic). I want to have a back-up as this one is getting long in the tooth..It's on an AQ260A, btw..
Many thanks!
Mike

 

[dubs283]

Re: Thunderbolt IV replacement Module

can't verify the part number for you right now, i do know they aren't cheap

about $700-$800 list price

not sure about aftermarket, maybe a search here on i-boats

sounds like you got a merc ignition on a volvo engine package

 

[Jaegerboy]

Re: Thunderbolt IV replacement Module

Thanks, dubs..I am honestly a bit confused about which one I need, hence the question. I think its a 22 advance, but not totally sure, and even then I seem to see a few different versions of the TB IV with that total advance…for the motor and ignition, I'm biased, but do think that I have the best of both worlds with the volvo drive and TB IV ignition. Love them both...

 

[dubs283]

Re: Thunderbolt IV replacement Module

22 deg sounds right, would want to verify with a volvo manual for your package for sure

thunderbolt ignitions are pretty stable, the only issue I have had with the older style modules like in your pic is 1) they DO wear out, especially being 30 years old and 2) they dont want to work properly with newer style ignition sensors, there is a problem with an idle timing jump of 4 degrees or so

 

[Jaegerboy]

Re: Thunderbolt IV replacement Module

Thanks again, dubs. I'e replaced the distributor within the last year or so, along with sensors and didn't notice any jumping around. That ignition just purrs. But as you say, getting old and want to have that backup. You're right of course, I'll check that advance but do believe it's 22. It you come across what you think is the correct replacement, I'd love to know. Been looking at a few for a while, and not sure why I can't seem to figure it out...

 

[achris]

Re: Thunderbolt IV replacement Module

I'll take a guess and say that an AQ260A is a 350GM engine. In the Mercruiser range of 350 engines, some had 22 degrees of advance, some 24.

That module is the first generation of the Thunderbolt IV modules. As already said, it's no longer made. The easiest and cheapest route for a replacement might be one of the newer Thunderbolt V modules. They are a straight replacement, using the same dissy and sensor in inside the dissy. I believe they also come with a harness to make them plug and pray compatible...

This service bulletin should help you with identifying your module and what replaces it.

http://www.marinemechanic.com/merc/...lder/thnbolt-IV-module-replacements_EN_14.pdf

Chris.........

 

[Jaegerboy]

Re: Thunderbolt IV replacement Module

Thanks, Chris…
Greatly appreciate it. And yes, the 260 has a total advance of 30 (with the 8*BTDC.)
Thanks to both of you.
Mike