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Mercruiser 454 ignition question.

A

Ajd1979

New member
I have a 1988 Baha Cruiser with twin 454's. The starboard engine quit last trip and has no spark. Both engines have DUI distributors. I've done some digging and believe I have a bad ballast resistor. From what I've researched that ballast resistors are mostly needed for points style ignition systems. With the newer DUI ignitions on the engines are the ballast resistors needed, or should I just go ahead and leave it on and replace it with a new one?
 
A photo of distributor would be good.
You say DUI. Are you 100% sure thats the brand?

In 1988 I believe all mercruiser engines were running Thunderbolt IV electronic ignitions and NO resistor wire as was ised in older point ignitions.

So lets get the exact ignition determined
 
DUI's don't need a ballast resistor....don't know what was installed before hand but assuming it was a factory points style distributor, MCM didn't use a traditional ballast resistor - the harness has a length of resistor wire instead. The factory manual validate what KGhost said - the 7.4's used TB-IVs...

FWIW, DIU's install sheet says they want a 12 AWG conductor to supply primary current to their coil...no ballast resistor...
 
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