1996 Mercruiser 454 with a Thunderbolt V ignition (mounted on distributor). The instrument side of the canon plug was cut by a previous owner making it impossible to secure the plug with a hose clamp. I've had corrosion issues in the plug on and off since buying the boat in 2009. Last season I started having stall issues coming off 3/4 to full throttle. Engine would stall and smell flooded. With the captains call open, on take off I can hear a slight miss/popping noise through the exhaust. The engine had a complete tune up and carb rebuild 2018. I purchased a used instrument side canon plug and spliced it in. While cutting the wires on the boat, I noticed the wires were black up into the insulation. My suspicion is the corrosion is also present on the motor side of the plug and the added resistance is messing with the operation of the thunderbolt ignition module. Anyone have any other theories? If the engine side is also corroded, would you recommend spending a small fortune on a replacement ignition module or is their an alternative replacement for a thunderbolt which doesn't require a ton of changes to the engine?
