Mercruiser 4.3 spark from coil but not cap

jbizub

Recruit
Joined
May 18, 2019
Messages
4
Hi All,

Weird issue, Boat was having running rough and stalled. Fuel pump stopped working. Found it lost 12v. I have it coming direct from key switch for right now for testing. That all works ok now. I changed cap and rotor earlier today before any of these issues occurred. I have spark coming out of coil. But its not sending it to the plugs. I pulled cap and rotor back off and it all looks ok. I did the thunderbolt spark testing procedure and I have voltage at the red/white wire underneath the distributor. Any ideas on what you think could be causing this?
Thanks,
Justin
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,723
If it's coming from your coil, then your problem is coil wire, cap, or rotor. Did you try putting the old stuff back on?
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,310
Ayuh,..... Welcome Aboard,..... What vintage 4.3l,..??

Carbed,..?? Which carb,..??
Efi,..??
Mpi,..??
 

jbizub

Recruit
Joined
May 18, 2019
Messages
4
Thanks everyone, that was my thought that it has to be cap /rotor. I know the lead going into the distributor cap is good because my tester lit up. I am going to put my old cap and rotor on today. I'm hoping some gear in the distributor didn't snap. It's is a 94 carb 4.3
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,310
I'm hoping some gear in the distributor didn't snap.

Ayuh,..... If yer getting any spark, the distributor is turning,......

The primary circuit is fired by the module in the distributor, 'n the 2ndary circuit then runs through the cap, 'n rotor,....
 
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