Coil

Twainer

Petty Officer 2nd Class
Joined
May 10, 2016
Messages
163
I have noticed while adjusting on my carb that the coil is very hot. The ignition has been converted to electronic ign. 1. Is the coil supposed to be hot? 2. Is the coil output voltage for points & electronic the same?
This thing looks old... like maybe the original which by the way is a 1977 351W. Didn't know if I need a better coil for elec ign. I kinda of remember that engines back then a coil is a coil. The only difference was between manufacturers. Fords was several thousand volts higher than GM & Mopar.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,307
points run with 9 volts except for cranking which is 12 volts. the 9 volts is by either a resister wire or a ballast resistor

some coils need the ballast resistor, some coils do not. if your coil is the original, it would require the ballast resistor. when you converted to electronic. did the instructions tell you to change the coil or run a ballast resistor. go back to the instructions

coils get hot if the key is on and the motor is not running

there are dozens of coil types out there, more than just output voltage. Ford, GM and Mopar as well as the rest of the automotive world all bought coils from the same companies. so you can believe all the hype you want. output voltage depends on windings and dwell time and will change a bit thruout the operating RPMs
 

Twainer

Petty Officer 2nd Class
Joined
May 10, 2016
Messages
163
I did not convert it myself but I will take a look to see if it has a ballast resistor on it. Boat was running when I noticed the heat. This might be normal so I might be getting bent out of shape for nothing.
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
70,468
This might be normal so I might be getting bent out of shape for nothing.

Ayuh,.... Unless yer chasin' runability issues, I believe this is correct,...

Everything on a motor runs from 'bout 140? to 180?, which is very Hot, to the touch,....
 

centerline

Seaman
Joined
Sep 8, 2008
Messages
57
all common electronic ignition modules are designed to work with a 1.5ohm coil, without a resistor... but a coil can get fairly warm when the key is on and the engine isnt running... if it gets so hot you cant hold your hand on it for a couple seconds, there is something wrong with the system and the coil is in in danger of exploding.... its not a big explosion or any electrical fires or anything like that, it just blows the top out of the coil and spreads hot smelly oil around and makes a mess, and leaves you without an ignition coil...
a hot coil needs either a resistor added in the ignition wire before it connects to the + post of the coil.... or the proper coil installed.
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,056
I am going to guess that you have a Petronics conversion. I just googled their site and if that is what you have it is compatiable with your current resistance wire. Of course they also say that for maximum results to add their coil. Check it out for your self. I have installed them several times with good results.
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
...... I just googled their site and if that is what you have it is compatiable with your current resistance wire. ......

I have have seen many instances that Pertronix did not do well with resistance sources like wires and ballasts. ....and I do believe that Pertronix blaster coils want a full 12 volts.
 
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