1972 Chrysler 55hp Burning Up Coils

Fabuglas

Seaman Apprentice
Joined
Oct 18, 2012
Messages
38
This motor runs great with one expensive exception, it burns up ignition coils.
The replacement coils are very expensive. The boat is used in Milwaukee which has a short boating Season. In addition, the boat is launched maybe 10 times a Season. The motor burns up on average every 1.5 Seasons.

Is there something in the electronics of this engine that could be bad causing the coils to overheat? I'm running the factory replacement coils.
If I can't find the source of the problem, is there a cheaper coil I can run?
 

ct1762@gmail.com

Master Chief Petty Officer
Joined
Jan 17, 2019
Messages
858
yes... the condensors need to be absorbing enough voltage. but keep in mind if the ignition is on, it will constantly feed 12v to the coils. id think that would also damage the points. i changed mine to the gammatronix setup used in motorcycles with the same ignition. amazing. points will virtually never wear out and it idles so much better. now the computer does the switching, not the points.
 

ct1762@gmail.com

Master Chief Petty Officer
Joined
Jan 17, 2019
Messages
858
yes... the condensors need to be absorbing enough voltage. but keep in mind if the ignition is on, it will constantly feed 12v to the coils. id think that would also damage the points. i changed mine to the gammatronix setup used in motorcycles with the same ignition. amazing. points will virtually never wear out and it idles so much better. now the computer does the switching, not the points.
also the coils need to have a ballast resistor and are NLA but you can use others of the same spec. which ones are you using?
 

Fabuglas

Seaman Apprentice
Joined
Oct 18, 2012
Messages
38
also the coils need to have a ballast resistor and are NLA but you can use others of the same spec. which ones are you using?
I didn't know about the ballast resistor. That should be an easy thing to check. I don't have the repair manual with me but, will look at the wiring diagram to see where it's located, make sure it's there, and measure the resistance. It's a boat my Son and I restored for him. It's his boat. He is religious about removing the key from key switch when the motor is off. That said, I'll take a meter and just confirm that "Off" is truly off. Points are not the problem. If I replace the coil, spark to plug comes back reliably.
 

Fabuglas

Seaman Apprentice
Joined
Oct 18, 2012
Messages
38
Oh, I'm using the coils that are listed as the replacements. I've been buying them from Discount Marine Parts. They don't come in a factory box or bag so can't say for sure. Last time I purchased one I think it was around $130
 

ct1762@gmail.com

Master Chief Petty Officer
Joined
Jan 17, 2019
Messages
858
Oh, I'm using the coils that are listed as the replacements. I've been buying them from Discount Marine Parts. They don't come in a factory box or bag so can't say for sure. Last time I purchased one I think it was around $130
yea not cheap! but they should have the resistor built in. id need to check my parts book for my 67' 55 seaking
 

ct1762@gmail.com

Master Chief Petty Officer
Joined
Jan 17, 2019
Messages
858
id think a bad ground could cause damage. the frame / lower pan ground can go bad. i grounded mine to the block
 
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