thunderbolt amplifier

O

omc cobra guy

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I'm wanting to know if the Thunderbolt IV amplifier 22 has the same functionality as the 22a? Can I swap them without issues?
 
O

omc cobra guy

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Messages
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Re: thunderbolt amplifier

Thank you for the info "fun times"!! This raises some interesting questions but first a little history. I bought the boat used after about 50 hours I started to have some missing at 2800 Rpms after replacing the cap, rotor, plugs, plug wires and not fixing the problem I did some research. I found that to be one of the classic symptoms of the "amplifier" gone/going bad are those exact symptoms. Not knowing what it was or where it was located after more research I located it and started to remove it at that time I noticed the screws were loose coincidence? I thought so until I got it removed and found one of the terminals was broke off and laying in the bottom of the connector body so at that point I pretty much knew somebody had been working on it before. So I started my quest to locate a new one I found one that matched the numbers so I installed it problem solved. BUT while searching for a new one I found that there were a few different part # available which brings me to this point wondering if the replacement I got even though it matched what I took off did they truly use the correct part number? According to the tec bulletin you had provided a link for and matching the valve cover "A" (what a strange way to find a part number) I should have the v8 24 but what I took off was the 22 so my next question would be being as the advance curve is slightly different am I really going to notice it? I didn't notice any back firing, missing. I think this info would have to be taken into account also. The application is a twin screw cruiser operating in the cruising range of 1800-2800 to me it looks so close up to about 3400 range that its a none issue but I'm not an expert.
 
Fun Times

Fun Times

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Re: thunderbolt amplifier

First, Do you have your engine serial number by chance? The serial number may help tell us what one should have been on there.
 
Fun Times

Fun Times

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Staff member
Joined
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Messages
9,120
Re: thunderbolt amplifier

omc cobra guy said:
According to the tec bulletin and matching the valve cover "A" (what a strange way to find a part number) I should have the v8 24 but what I took off was the 22 so my next question would be being as the advance curve is slightly different am I really going to notice it?
The application is a twin screw cruiser operating.
Click to expand...
As you know, something's not really adding up! Your engine serial number shows you would have had valve cover B, which uses module part #15899A1 (22) http://www.mercruiserparts.com/Show...bnbr=240&bdesc=CYLINDER+HEAD+AND+ROCKER+COVER

For reference, valve cover A looks to be used in 1985-86 while cover B started in 87+. Cover A, http://www.mercruiserparts.com/Show...bnbr=170&bdesc=CYLINDER+HEAD+AND+ROCKER+COVER

Your serial number parts catalog, http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=816596

Your matching valve cover (A) parts catalog, http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=99985.
The amplifier can be found near the bottom under Wring Harness And Electrical Components if this is really what you have.

Service Bulletin 2009-14

Where was the module mounted, Distributor or exhaust manifold?

Do both engines look the same? What year is the boat?

As far as specifications between the two, there is some small differences but if you still suspect the module not to be the right one, for a quick test, you could try setting the total advance at 32* @ 3700 RPM to see if there are any changes. Also make sure the module is advancing like it should and ensure the ground wire going to the module is good clean and tight.
 
O

omc cobra guy

Cadet
Joined
May 14, 2012
Messages
22
Re: thunderbolt amplifier

Fun Times said:
As you know, something's not really adding up! Your engine serial number shows you would have had valve cover B, which uses module part #15899A1 (22) http://www.mercruiserparts.com/Show...bnbr=240&bdesc=CYLINDER+HEAD+AND+ROCKER+COVER

For reference, valve cover A looks to be used in 1985-86 while cover B started in 87+. Cover A, http://www.mercruiserparts.com/Show...bnbr=170&bdesc=CYLINDER+HEAD+AND+ROCKER+COVER

Your serial number parts catalog, http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=816596

Your matching valve cover (A) parts catalog, http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=99985.
The amplifier can be found near the bottom under Wring Harness And Electrical Components if this is really what you have.


Service Bulletin 2009-14

Where was the module mounted, Distributor or exhaust manifold?

Do both engines look the same? What year is the boat?

As far as specifications between the two, there is some small differences but if you still suspect the module not to be the right one, for a quick test, you could try setting the total advance at 32* @ 3700 RPM to see if there are any changes. Also make sure the module is advancing like it should and ensure the ground wire going to the module is good clean and tight.
Click to expand...

Its a 1995, both engines look the same and the module is mounted to the back of the distributor. Just my luck I got ahold of a bastard :facepalm: is it possible I got an engine that was changing for the next model year although with the dates you mentioned that could not be possible if my engines are 1995. I m finding a different part number from what mentioning. ref Go To Marine
5.0L (2 BBL.) GM 305 V-8 1988-1995 0B774445 THRU 0F600999 (MERCRUISER)

ELECTRICAL COMPONENTS(IGN. MODULE MOUNTED ON DISTRIBUTOR)
23 805361T3 MODULE, Ignition | (200/230 - 5.0L/LX) THUNDERBOLT IV $324.79
23 805361T4 MODULE, Ignition | (260 - 5.7L ALPHA) SN# 0F273497 & Below $258.00
23 805361T6 IGNITION MODULE | (260 - 5.7L ALPHA) SN# 0F273498 & Up $304.30
23 805361T4 MODULE, Ignition | (5.7L BRAVO) SN# 0D617327 & Below $258.00
23 805361T6 IGNITION MODULE | (5.7L BRAVO) SN# 0D617328 & Up $304.30
23 805361T4 MODULE, Ignition | (350 MAGNUM) SN# 0D617327 & Below $258.00
23 805361T6 IGNITION MODULE | (350 MAGNUM) SN# 0D617328 & Up $304.30

I think at this point when the weather breaks I'm going to look at the module that's on the port engine that's the one that I've haven't had trouble with to see what module is on that one. As mentioned above this being a cruiser and the chance of operating this over 3400 rpm is slim, I wonder if its really going to mater in the end as long as they are the same one both engines or even if the advance curve is so close to each other in that operating range if one is different?
 
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