Ignition Switch Issues

[freelunch]

Hello all, its been a while since I have posted.
I have a 1972 Chrysler 120 and am having difficulty getting my new ignition switch to work.
I don't have the old one so I am not sure to hook it up.
The replacement part i have is a 6 terminal Sierra ignition switch heres a link to it
http://www.boatersworld.com/product...cielectrical-boat;cipanels-wiring;ciswitches-
Hopefully someone has had this problem before as all this switch does is turn on battery power and activate the choke.
Thanks all for your time,
Danny

Oh and the new switch also calls for a magneto circuit, and I have no idea what that is, please help

 

[Frank Acampora]

Re: Ignition Switch Issues

Marines were originally a part of the Navy---Hence the term "Marine."

But anyway, your 72 Chrysler does not use the two "M" magneto terminals.

Under the dash, from the engine multi wire cable, YELLOW goes to the "S" start terminal. Green goes to the "C" choke terminal, Red goes the the "B" battery terminal, and Blue goes to the "I" ignition terminal. The overheat indicator has one wire connected to the "I" terminal also. The other wire from the overheat indicator connects to the orange wire. Since the two "M" terminals do not connect with anything else in the switch, It is acceptable to terminate the second wire from the overheat indicator and the orange wire to the SAME terminal for convenience and to keep them from flopping around under the dash. IMPORTANT: If you do this be sure that the other "M" terminal is insulated and not used. When the ignition switch is off, the two "M" terminals are connected to each other (in continuity). Some schematics show the white tach wire connected to an "M" terminal but I prefer to keep tach signal away from the ignition switch.

I don't really pay attention to engine years but I think your 1972 has electronic ignition fired by points. If this is the case, At the engine terminal board the wiring is this:

FROM THE TOP:
Yellow-----Start
Purple-----connected to terminal but not used.
White----- Tachometer connection.
Green-----Choke
Orange----Overheat indicator circuit
Red-------Battery
Blue-------Power to CD box.
Black -----Ground

All wires in the engine cable connect like color to like color.

"I" terminal on the switch is a switched terminal and supplies power to engine ignition and accessories (gauges and overheat indicator) only when the switch is in the run or on position. When you turn off the switch, "I" terminal has no power, no voltage goes to the CD box and the engine stops for no spark.

Now, I don't believe it does, but if your engine has battery, points, and coil ignition, the blue wire supplies power to the positive side of the coil which the points switch on and off through the negative side.

If the engine is not cranking you need to check that the neutral interlock switch--A brown switch with a white button connected either on the distributor or below the bottom carb-- Is properly adjusted and the button is being depressed in neutral. Depressing the button allws voltage to energise the solenoid and fire the starter motor. Sometimes with old engines, the cables are sloppy and when the control handle is returned to neutral, the linkage does not depress the button--Jiggle the control through forward and reverse and then re-try to start.

 

[freelunch]

Re: Ignition Switch Issues

Wow thank you so much, that was a great reply.
I'll be sure to let you know how it all works out.
And although we are under the department of the navy its been at least 200 years since we served our original maritime duty of shooting enemy personnel from our ships masts and rigging.

 

[freelunch]

Re: Ignition Switch Issues

Hey Frank I have another question regarding the overheat indicator circuit.
I should have specified I am finishing a center console conversion and I do not have the actual overheat device which should be located on the dash.
I do however have the heat indicator switch located on the powerhead. The orange wire running from it does connect to the terminal block on the engine.
Do I need to by some kind of buzzer that will function on a closed circuit to replace the dash warning device?
Thanks for your time,
Danny

 

[freelunch]

Re: Ignition Switch Issues

Ok well everything is wired per the previous post, however now I am tripping the circuit breaker when I attempt to start the engine, any ideas what the likely culprit could be?
Thanks again,
Danny

 

[Frank Acampora]

Re: Ignition Switch Issues

First you need to check for shorts. Check the switch terminals to see that no spade terminals are touching. Check the wires where they run under the flywheel. Sometimes they are slack, and rise up to touch the flywheel, rubbing off the insulation, and shorting. If this is the case, repair the wire and install a thin aluminum plate on top of them to keep them from rising into the flywheel. Remove the two alternator wires from the regulator and check for resistance. It should be low, but not 0 (indicating a shorted stator) If you have a large condenser on the engine terminal board, check it for shorting. Disconnect it from the terminal board. The engine can be started with it disconnected.

Turn on the key to the run position. Does the circuit breaker pop? No? the ignition circuit is ok. Yes-- Check for shorts in the blue wire and associated circuits (gauges etc). Did the engine run before you replaced the switch? No? possibly a bad CD box.

With the key in the run position push in to choke. Does the circuit breaker pop? Yes--either there is a short in the choke solenoid or in the green wire. No? choke system is OK.

Turn the key to start. Does the breaker pop? Yes--check for a short in the start solenoid or the yellow wires. No? Start circuit is OK.

Turn on key to start, and simultaneously push to choke. Does it pop? We already proved all systems to be ok, so the circuit breaker is bad. Buy a new 25 or 30 amp one at your local auto supply store.

Remember, I asked if you had points controlled electronic ignition. If you have a black CD box and one wire from it to the side of the distributor it is. If you have 2 wires running to the side of the distributor and one of them is blue, then you have an electronic distributor.

At this point, since you do not have an overheat indicator, nothing else (besides possibly tachometer and gauge power) should be hooked to the "I" terminal.

You can buy a standard generic buzzer at almost any marine store, iboats probably has them too.

 

[gregmsr]

Re: Ignition Switch Issues

Food for thought?
I was having a problem blowing fuses when activating the choke during starting. I went from a 10amp fuse to a 15amp and no problem sense.
Hmmmmmm........ Have I created a hazard?

 

[freelunch]

Re: Ignition Switch Issues

Thanks for the replies, the circuit breaker only trips when i hold the key in the start position for several seconds.
Would this lead me to the trouble area any faster ?

 

[Frank Acampora]

Re: Ignition Switch Issues

OK, Assuming you mean holding the key to start without choking, that narrows it down a bit. remove the yellow wire from the engine terminal and from the solenoid terminal. Using an OHM meter (VOM) check resistance between the each end and a good ground with the engine in neutral. It should read infinite ohms. anything else, and there is a short in the wire or neutral interlock switch. Physically check each yellow wire to be certain it is not worn and shorting.

Now, measure the ohms from the starter solenoid yellow terminal to ground. It should be low ohms but not zero. If it is zero ohms, the solenoid is shorted to ground and needs to be replaced,

Jump from the battery side of the starter solenoid to the yellow terminal on the solenoid. The engine should crank over (it will spark so be careful) If it does not, the solenoid is definitely bad--replace it.

If you are choking at the same time, then you need to check the green wire especially at the choke solenoid terminal. It is very close to the strap holding on the solenoid and can ground against it. Also check to be sure the insulator on the choke solenoid terminal has not broken.