Electrical Question

JasonB

Lieutenant
Joined
Feb 10, 2003
Messages
1,455
I just installed a new Pertronix kit and Pertronix coil in my Mercruiser 888. It is currently drawing its power from the resistance wire, which isn't the optimal solution. As I read the diagram, the key-on wire goes to the electric choke then to the ignition coil via the "resistance" wire. As I understand it, the power from this wire is only about 8 volts. Since it is split off the wire from the key, it doesn't look like I can tap the wire before the choke. Before I break out my Multi-meter, does anyone know where a good place to tap key on 12v power might be on this engine or is there something special about the "Resistance" wire" that drops the voltage sol that I could tap in before it?
 

gpane

Seaman Apprentice
Joined
Jan 29, 2003
Messages
30
Re: Electrical Question

i have a petronix kit installed on a '82 omc 305 with resistor wire and was told by petronix to either connect before resistor wire, which i couldn't figure out how to do, or run another wire from ignition switch to red wire of petronix module which i did and works fine.Check out there web site or call them, they are very helpful and will answer any questions you have.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,090
Re: Electrical Question

jason,<br />Tap in Before the resistor, or about any of the Purple wires, Should be Keyed 12V Power.....
 

JasonB

Lieutenant
Joined
Feb 10, 2003
Messages
1,455
Re: Electrical Question

Thanks guys. Is the "resistance wire" a special wire with more resistance to cut the voltage or is ait a resistance wire because of where it connects? I'm thinking the prior, but am curious to be sure.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,090
Re: Electrical Question

"resistance wire" = Ballast Resistor...
 

petryshyn

Commander
Joined
Oct 3, 2001
Messages
2,851
Re: Electrical Question

If it has a resistance wire, it is an actual wire which has much more electrical resistance than copper. Usually about 1 ohm per foot... :)
 

f_inscreenname

Commander
Joined
Aug 23, 2001
Messages
2,591
Re: Electrical Question

I just installed mine the other day. I rebuilt my boat and motor in the back yard (with all new wiring,gages,switches any thing to do with the electric) and that includes the motors electrical system. I wasn't sure weather I needed a ballast resistor or not, wasn't even sure if there ever was one. After talking to Pertronix they told me to check the coil for resistance (had to be greater the 1.5). It was so I could run the two wires from the igniter directly to the coil. So to stop all the head aches about wiring it right I would go to the local parts store and get a coil that has a resistance greater then 1.5. (mines the yellow Accel universal that's in every parts store) then you can get rid of the resistance wire and run straight to the coil, there is your 12 volt. Plus you can always use a new coil, they are one thing that doesn't get better with age.
 

JasonB

Lieutenant
Joined
Feb 10, 2003
Messages
1,455
Re: Electrical Question

Now that I understand what the wire does (first thought the voltahge drop was from somewhere else), I will tap my Pertronix/coil power lead in before it. I installed a new Pertronix 1.5ohm 40k volt coil, so as I understand it, it should have no problem with the extra voltage. Even with the resistor wire in there, she's purring like the proverbial kitten.
 
Top