470 project electronic ignition question

[fmalott]

i just did the conversion and i asked a question on a previous thread of mine called points to electronic ignition question. some one told me to remove the purple resistance wire from the coil + and tape it off out of the way. Splice a stranded wire directly into the wire going to the electric choke and run that to the coil +. That will give you full 12V to the Petronix module, and you should be good to go. my question is there is one wire going to the positive it's purple with yellow stripe is this the one also which wire on the choke do i use there is two wires i included pics of coil wires and choke wires

 

[achris]

Re: 470 project electronic ignition question

ok... '-' on the coil has 2 wires, one is Grey and is the tacho feed, the other goes to the points inside the distributor. On the '+' of the coil are also 2 wires, one is (or should be) purple, this is the resistance wire, and the other should be purple/yellow from the starter (feeds full 12 volts while cranking the engine).

On the choke you also have 2 wires, both purple, and here is were it could get tricky. One of those wires is directly from the key and will be full 12 volts, the other is the resistance wire to the '+' coil. What I would do is just add another wire to the connector at the choke and run it to the '+' of the coil. For ease, just add the new wire to the coil. Leaving the resistance wire connected won't hurt anything, and means you don't have a 'live' wire floating around to short out on anything.

Chris...

 

[achris]

Re: 470 project electronic ignition question

I've had another (closer) look at your pictures, nice quality and clarity by the way... Looks like on the coil '+' is red and purple/yellow, and on the choke is purple and red. By elimination the red wire will be the resistance wire. If you have an accurate digital multimeter you might be able to measure the resistance, it should be 1.8 to 2 ohms. Unless you have a Fluke (or similar quality) meter forget it. But being red makes me think that someone might have replaced it in the past, thinking it was just a 'normal' piece of wire. You might be in luck and be able to use that wire. But if in doubt, run another wire as I explained ^....

Chris........

 

[fmalott]

Re: 470 project electronic ignition question

ok let me get this straight never mind splicing and cutting just add a wire from the positive side of coil to the choke connector?

 

[thumpar]

Re: 470 project electronic ignition question

Unless you are replacing the coil with an internally ballisted coil you need to keep the resistance wire on the coil and run another wire with a full 12v to the pertronix module. When I did mine I just replaced the coil also and ran a new wire from 12v switched to the new coil that also feeds the module.

 

[achris]

Re: 470 project electronic ignition question

ok let me get this straight never mind splicing and cutting just add a wire from the positive side of coil to the choke connector?

I've never hooked up one of these Petronix modules, so don't know the specifics of the installation. But if i the instructions say run a 12 volts wire to the coil '+', then that's all I'd do, run a wire in parallel with the existing resistance wire.

PM me for an email address to send the installation instructions and I'll have a read and let you know what they require...

Chris......

 

[achris]

Re: 470 project electronic ignition question

Just found the installation instruction on the interweb... I would just run a new (purple) wire from the choke connector to the module...Leave all other choke/coil '+' wires in place. Job done!

 

[fmalott]

Re: 470 project electronic ignition question

sorry for the old pictures that's the old with the points. what i did is when i put the new coil on i put all the wires from the old coil positive back on the new coil positive and the same with the negative the new module it had two wires one red and one black it asks you to put the red on positive and the black on negative where do i go from here, achris it sounds like you want me to take that red wire from the module off the positive and run it to the choke wire is this right
ps it one of those petronix kits

 

[stonyloam]

Re: 470 project electronic ignition question

Little confusion here. First the purple/yellow wire (on a 470, unlike many other Mercruiser engines) provides battery voltage (12V) from the slave solenoid when the starter is turning and should be left in place. I believe the resistance wire is a slightly different purple color than the 12V choke wire (both are really purple in photo just the camera sees them differently) , check and splice into the 12V side of the choke connector. You can leave the resistance wire on if you like, removing it just lessens future confusion. Once you are sure you have a full 12V to the coil + attach the red Petronix wire to coil +, the black one to coil -. Hope that helps.

 

[fmalott]

Re: 470 project electronic ignition question

ok i think i get the message

 

[stonyloam]

Re: 470 project electronic ignition question

ok i think i get the message

Let us know how it works out. When I put mine in I had no idea what I was doing, finally got it right and runs great. Glad to help someone learn from MY mistakes.