schwarz633
Member
- Oct 1, 2019
- 35
- Boat Info
- 1989 Weekender
- Engines
- Mercruiser 5.7 Inboard Straight Drive
I recently upgraded the ignition system on my 1989 300WE 5.7 to DUI HEI distributors. I have the distributors, coils, and Thunderbolt IV modules available. Also new Mercruiser caps and rotors, one set unused and the other set has about 20 hours on them. When one of the engines lost spark, I originally thought the module had failed, but subsequent parts swapping proved that to be incorrect as both modules are functional. Either one of the coils is bad or the pickup module in one of the distributors has failed.
