1968 35hp magneto wires

[lady riverrat]

I recently replaced the ignition switch to my 1968 35hp Mercury but every time I hook the wires up going to the magneto they begin to smoke. I asked the technician at the parts dealer, I tried his way and it still smokes. It has a Phelon Magneto. The wiring diagram shows the white and salmon wires going to the magneto. The diagram and the switch have different letterings. The switch has M, M, B, C, S, I. The wires I have are
Red to B terminal (Battery)
Grey to C terminal (Choke)
Yellow to S terminal (Starter)
Black to M terminal (Ground)
Salmon
White
I have tried switching the terminals on the salmon and white wires I know one should go to the other M and the other to the Ignition (I) but it will smoke either way. Any ideas?

 

[corm]

Re: 1968 35hp magneto wires

Hi,

I do not have a wiring diagram for your engine or for the switch you bought.
However if your magneto is smoking you are putting 12 volts into your coils.
This is bad! You will, if not already, burn up your ing system. It is a magneto not a battery ing. There should be no current to the ing sys. Find a wiring diagram before proceeding.

 

[lady riverrat]

Re: 1968 35hp magneto wires

Thanks I have a wiring diagram but it still smokes. I talked to someone today that said it was probably the stator has gone bad but I have not had much luck finding a stator for my year model.

 

[Fuzzytbay]

Re: 1968 35hp magneto wires

You can find the wireing diagrams for your engine here. NOTE......DO NOT use the wire colour as a guide in your harness. Check where each wire goes to, with an ohm meter. You can also find the ignition switch diagrams here as well. Good luck tracking it down. The stator will be bad if it has zero to ground on either of the two wires. OR if it has zero ohms resitance between the two yellow wires.
http://www.maxrules.com/wireindex.html

 

[corm]

Re: 1968 35hp magneto wires

Hi,
I'll bet you a dollar you don't have a stator and your running 12 volts into your coil and condenser. You point return spring is probably blue colored now too.

Your engine colors Thanks to Fuzzytbay.
Gray is the choke.
Yellow is the starter solenoid.
Red is the battery positive.
Black is the Battery negative.
White is one point.
Yellow is the other point.

Now you have match up you switch to the above and see what you have left.

I am going to take a guess at your switch.
B) is the positive battery (red).
S) is the Solenoid ( yellow)
C) is the Choke (gray)
M) is the battery negative (black)
M) The other M is where you will hook either the white or yellow wire up to.
Do not but both wires on this terminal or you will ground out the ignition and it will not start. Tape off the wire you have left(white or yellow).
I) Do NOT put it on the I terminal as this puts 12 Volts in to your ing system. (like I was saying in another post)

Now when you turn off the engine only one cylinder will ground out. So if you have a good running engine it will run on the one cylinder that is not grounded out ie the wire you have taped off (white or yellow). You may have to choke your engine to kill it if it still runs on one cylinder. They will usually die do to low RPM.

The ignition switch you have was made for a single point distributor system or a CDI ignition system not a dual point magneto ignition system. IMO

If I remember right some switches with the double M terminals allowed for each magneto wire the be connected to them (white and yellow) However without seeing a wire diagram or a meter on your switch I would not personally try it.

With a VOM meter.
You could hook up everything but the white, yellow and ground and see if it works. If everything works (starter & choke) take a meter and check to see if you have a circuit between the two M terminals with the switch turned off. If you do with no voltage showing on either M terminal turn the switch to the on position and see if you have any voltage on either terminal and that the circuit is open between the two M terminals. If there is an open circuit and no voltage you could hook the yellow to one M and the white to the other M terminal. This has a slim chance of working, but you never know unless you try it. If by chance it works the switch will ground out both points together and kill the engine. So you would not have to choke it to stop it.

 

[P33dy01]

Re: 1968 35hp magneto wires

I know your post is old, but I'm having the exact same problems. The only thing I did differently is that I placed the salmon and white wires on each of the M posts. I'm still getting a weak spark. Do I need to use the ground wire on one of the M posts? How did your problem ever turn out for you? I hooked my old switch up improperly and it smoked from underneath the fly wheel as well. So I'm interested to see if you had to replace the coils, points, etc... Let me know how it turned out for you please!

Thanks,