Mercrusier,233hp,341w,1977, confirm fix for pertronic ignition dist/coil no run probl

Capt Matt

Cadet
Joined
Aug 11, 2010
Messages
8
Ive been restoring this old boat since 2008. When I bought the boat it ran like a champ. But lost the motor in a freeze. found a replacement that I upgraded. Thought I would have it in the water last year but ended up with this problem. Engine would crank over, start but shut down when ignition went back to run. I hot wired a 12 volt line to the coil and it would run but due to my research at the time it was not supposed to have 12v all the time to the coil but drop to something like 4.5 - 7 when running. One of the upgrades was a Pertronix distributor and a Pertronix igniter II. I have found many references to this and similar problems on this site. This is what I have learned, the set up now has 2 joined tan wires from the boat and the red wire from the distributor to the + on the coil and the black distributor wire to negative on the coil.

The is also another wire to the negative, its origin is unknown to me today. I think it is dark brown, possibly black from the wire loom. I read that a purple wire was in the mix for some of the owners problems, possibly a ballast wire. I recall seeing one on one side or the other of the main engine loom plug but on one side or the other there was none? If my memory (which is highly in doubt these days) serves me correctly the brown wire may have been for a ground to something else. I will have to unwrap it and figure out what it was for.

Now back to the coil. I believe I understand the two tan wires were the ballast wires and are not needed with the electronic system I now have.

Am I correct that one of the tan wires comes from the electric choke where there should be 12v? If so can I use the connection for the 12 source with a new wire, not the tan wire

So I get rid of the tan wires, replace with a switched 12v source and the Red Dist. wire on the plus side.?

Get rid of the dark wire on the negative side and use only the black Dist. wire?

All should work at this point. Yea, Nea or What?

Thanks in advance for your expertise.

PS I'm still waiting to see if we have anymore freeze's here before I de winterize and see if this thing will ever run in California waters.
 

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: Mercrusier,233hp,341w,1977, confirm fix for pertronic ignition dist/coil no run p

So I get rid of the tan wires, replace with a switched 12v source and the Red Dist. wire on the plus side.?

Get rid of the dark wire on the negative side and use only the black Dist. wire?

All should work at this point. Yea, Nea or What?

Thanks in advance for your expertise.

PS I'm still waiting to see if we have anymore freeze's here before I de winterize and see if this thing will ever run in California waters.

Bottom line - you need the full 12v switch power to the + side of the coil. The red wire from the Ignitor to the + side. The black wire from the ignitor to the neg side of the coil. You will also need a wire from the neg side of the coil that goes to your shift interrupt switch.
 

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: Mercrusier,233hp,341w,1977, confirm fix for pertronic ignition dist/coil no run p

Here's how the Pertronix is wired:

pertronixwiringdiagram.jpg


As I mentioned, the only other wires will be the negative wire to the shift interrupt. (And if you have a tach, it will be connected to the neg side of the coil as well).

Oh yeah - welcome aboard! ;)
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
Re: Mercrusier,233hp,341w,1977, confirm fix for pertronic ignition dist/coil no run p

Make sure you don't ground the - on the coil. You will never get spark. There should only be the pertronix wire and tach wire on the coil.
 

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: Mercrusier,233hp,341w,1977, confirm fix for pertronic ignition dist/coil no run p

Make sure you don't ground the - on the coil. You will never get spark. There should only be the pertronix wire and tach wire on the coil.

Plus the wire to the shift interrupt.
 

Blueghost924

Petty Officer 1st Class
Joined
Sep 19, 2013
Messages
250
Re: Mercrusier,233hp,341w,1977, confirm fix for pertronic ignition dist/coil no run p

I'm going to have to keep this post bookmarked as this weekend I'll be doing the Pertronix upgrade to my Mercruiser 470. Hopefully with the research on IBoats and the Pertronixs instructions, it will be a success. Great diagram.
 

Capt Matt

Cadet
Joined
Aug 11, 2010
Messages
8
Re: Mercrusier,233hp,341w,1977, confirm fix for pertronic ignition dist/coil no run p

Thanks guys for all the replies, we have a week or so of weather coming through but the next decent day I will de winterize and work on these changes and see if it works. I'll follow up here when I have. It was those dam ballast wires the screwed me up and I didn't want to burn up the electronics using the full 12 volts. Live and learn.

Thanks again, seems like were on the same page now. Just have to find where that odd wire go's, could be the tach.
 

haulnazz15

Captain
Joined
Mar 9, 2009
Messages
3,720
Re: Mercrusier,233hp,341w,1977, confirm fix for pertronic ignition dist/coil no run p

The tan wire to the choke should also be 12V by the way, as it gets it's power BEFORE the ballast portion of the tan wire. A quick test with a multimeter with the ignition on will confirm that.
 
Top