Question regarding Electronic ignition conversion, coil resistance.

Alter Bootsmann

Seaman Apprentice
Joined
Jun 11, 2011
Messages
34
I just converted my Mercruiser 888 to electronic ignition today. It is a 1973 model that had been rebuilt in '88 and the original distributor was replaced then by the original owner. He replaced the original distributor with an Excel dual points automotive type. I bought the boat in '95 and it has worked fine since then. However I have wanted to do the electronic conversion for a while. Since the distributor (Excel) is not a Marine type and I probably could not get a Pertronix kit for an aftermarket dist anyway, I chose to go with the Mallory Marine magnetic switching type distributor. Mallory Marine YLM512CV is what I have installed.
Here is where I need help badly. I was told by the instructions to wire the unit one of 3 ways, all pertaining to the type of coil I currently have in use.
Instructions say if you have an external ballast type resistor for the coil to wire it one way, the other two options are actually wired the same.
One of these two methods has a wire type resistor inline with positive terminal of coil.
The last option is for a coil with enough internal resistance. On both of these types of installs you wire the red wire from the distributor directly to the + terminal of coil.
What I don't truly know is whether or not my coil has enough impedence to handle this or not? I measured resistance across the + and - terminals and got around 1.9 to a little over 2 ohms.
I don't know if my current coil is the original or not. It has Delco Remy 293 B-R on it.
I called Mallory and the tech said he believed I would be OK wiring it as stated in the later discription.(red wire to + terminal directly.
Well I installed the distributor and the boat started right up immediately. I set the timing and she runs great. However the thought that I may have wired it incorrectly is driving me nuts. I am afraid I will burn my new distributor up.
When I looked up the original Mercruiser coil for my boat. The pictures show a coil that says "must be used with external resistor."
I also believe I am correct in saying that all working coils have a minimum impedence anyway so I am just stumped. Does anyone know if I will be OK the way I have it installed?
Thank you!
 

Pete104

Lieutenant
Joined
Apr 30, 2011
Messages
1,439
Re: Question regarding Electronic ignition conversion, coil resistance.

I'm thinking do some research on that Delco coil you have. B-R probably means that it is internally resisted.

Mercury did use a "resister wire" compared to like OMC did use a "ballast"!
 

Alter Bootsmann

Seaman Apprentice
Joined
Jun 11, 2011
Messages
34
Re: Question regarding Electronic ignition conversion, coil resistance.

sorry for double post.
 
Last edited:

Alter Bootsmann

Seaman Apprentice
Joined
Jun 11, 2011
Messages
34
Re: Question regarding Electronic ignition conversion, coil resistance.

Update: I found the wiring schematic for my engine and it does have a "loom wire resistor" built into the primary ignition circuit. So I bought a coil that does require and external resistor and everything is just Peachy.
I might say that adding the Mallory Marine magnetic pick up distributor was an excellent choice. My boat starts and idles better when I am trolling now so I am a happy boater. NO more points adj, yeah!
 
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