Thunderbolt IV question/ issue
 

I have a twin engine boat and my port motor keeps giving me problems. I have TB IV ignition system. It seems I keep seeing these system for sale on many message boards... Are they a bad system? Should I stay with it or switch it.... I have bought several used amps/modules w/ harness and the problem hasn't changed. Used ones all seems to have corrosion on the connections also just like my old one had... Is this the issue with why people are selling their units? Because they are having problems too...... I just recently bought I brand new amp/module and harness that I have installed but haven't had a chance to test run....

Running problem with boat:
After I run it about 5-10 minutes it starts running like crap... I notice that the amp/module is hotter than I think it should be on that motor. I can sometimes try to reconnect the harness and it will run good again for a short time and then crap again. Seems to have bad connection because of corrosion?.. If this NEW amp/module doesn't fix it what are your suggestions.....?

TB IV is a good system, but heat kills the modules. I had the exact same problem you have, but mine would die and not restart until it cooled down. I needed up putting in a high vibration MSD coil and had no issues. Also, make sure your modules are identical, since you have duals. The TB IV modules come are available in a slew of advance curves.

I installed some DEI heat shield mat on the back of the module to protect it from heat. I'm not sure it makes a difference but any bit helps.

Did you install the MSD coil to help with heat issue? If so, How does it help? I will research DEI heat shield mat also.....

JONSEYFXR, Coil, that is what I was thinking also.
+1 on checking the part # on the module Make sure they are the same.

The reason a lot of used modules enter the market place is because 90%+ of people thinking that an MSD system will make more horsepower on their mild motors.

Yes, incorrect thinking, but heh.....it helps the used market.

I had the exact same problem and wound up being this. http://www.michiganmotorz.com/thunde...97-p-3172.html

I bought the Sierra one and it would not run. Put in a Merc one and problem solved. Before That I tried replacing the coil and it did not help.

Chris

I have tried a couple of different model modules but adjusted the timing accordingly..... I now have two exact V8 modules on it.... But please explain why MSD high vibration coil may help? I need the knowledge..... thx, russell

Just make sure you replace coil, Mercruiser will be fine.
You cannot adjust the timing to make different modules the same. Same total or base yes, but, both or internal curve NO.

You cannot adjust the timing to make different modules the same. Same total or base yes, but, both or internal curve NO... Agreed... I did just for testing because they were available and used same total....thx...r

So, you guys think the coil maybe causing the module to get hot..... I will replace it regardless as it is old........ thx...r

It won't help.