Started out as a good day on the water. 4.3 mercruiser

[Scott06]

Why would you replace the ignition system if it’s working? The atB is a great system until the ignition module needs to be replaced $$$. Then typical replacement is a delco est. this isn’t any better except module rEllacement cost. Both are OEM quality systems.

friggin auto correct...

I meant the Merc TB (thunderbolt) is a great system, Merc just screws the owner by NLA or insane ignition module prices... so when the module dies a actual Delco Est (not cheap knock offs) is a good relatively drop in replacement.

Thanks everyone, I will keep everything intact as of right now. I will still order the 3 wire trigger, cap, rotor to keep on the boat as they are easy enough to change on the water if needed. I was hoping to go out again this weekend but the weather is not looking to great.

Yes the trigger sensor is not a bad replacement or keep one in the boat. Also keep a cap and rotor. I had to chisel my rotor off when I replaced it, so likely if you have to replace the trigger likely you will waste the rotor

 

[Lou C]

Why in the world does Merc seem to glue on those rotors? Talk about making a simple job a headache!
I’m curious how reliable the aftermarket modules are for the EST system are. It doesn’t sound like there’s a widespreaad problem so maybe it’s not a complex component to reproduce.

 

[Pmt133]

I don't know about the EST but I can say aftermarket HEI modules are typically ****.

 

[Lou C]

this is what I hear all the time in the Jeep world, aftermarket sensors, etc the only ones with decent reliability seem to be NTK, (crank sensors and O2 sensors) perhaps Standard Motor Products.....

 

[Scott06]

Why in the world does Merc seem to glue on those rotors? Talk about making a simple job a headache!
I’m curious how reliable the aftermarket modules are for the EST system are. It doesn’t sound like there’s a widespreaad problem so maybe it’s not a complex component to reproduce.

It seems to be hit or miss with the est modules , also finding an actual delco est is not as easy anymore. Mich Motorz no longer carries actual Delco for the 4.3 and 5.7, only the 3.0. When I bought my repower partial engine from them in 2015 they normally supply them with the EST. I had them sub a TB so I could keep it stock merc. I did buy two used modules on ebay. Only time i used the spare was when my kill switch acted up. Swapped the module to see if I got spark back.... then realized I just needed the cycle the kill switch...

 

[Pmt133]

the other thing with the GM HEI modules is that a lot tended to have specific quirks for their application. Latency comes to mind and a lot of aftermarket ones I've used and tuned on the 84 needed some massaging to work as well as the stock module in the spark tables.