Ignition switch problem?

[Shawnn]

My 860 will crank over but wont run. The tractors voltmeter (12 volt converted) is bottomed out (key in accessory position) except when I am cranking it over, at which point it reads 10-12v. Using my multimeter I see 12 volts at the battery and at the battery terminal on the ignition switch. I also get about 12 volts on the starter terminal when cranking. But I see no readout or less than 1 volt on the ignition terminal and acc terminal when key is in acc or run position. The tractors voltmeter is wired to the ignition terminal and had been working prior to today.

Is it safe to assume the ignition switch is bad? The connections on the switch seem solid and wires not very corroded. I can tell the tractor wants to run. It starts to run, so I stop turning the key...and it immediately dies and the voltmeter drops off.

Recently I had replaced a bunch of things related to the ignition system... Plugs, wires, coil, dist. cap/rotor and had it running great up until today.

 

[Sean in PA]

Does it use the key switch as the starter switch? That tractor originally used a push button neutral safety switch down on the top cover of the transmission. The original key switch did not have a "Start" position, it just turned everything except the starter on or off. It sounds like the original neutral safety starter switch has been bypassed and a key switch with a "Start" position is installed. My guess is that when that was done, a bypass wire was also installed to bypass the ballast resistor during starting and the bypass wire is providing power to the coil during starting, but the other wire that should be providing power from the "Run" position of the key switch to the solenoid isn't providing power to the solenoid. It could be that the "Run" position of the switch is bad, or it could be that other wire is bad.

 

[Shawnn]

Sorry, I should have mentioned the oem push button has been bypassed by previous owner. There is also no neutral safety switch either. Just a simple keyed switch with accessory. Power to the coil comes from the ignition term. on the switch I believe. It seems easy enough to replace the switch, just wanted to make sure I m not missing something

This post was edited by Shawnn on 02/23/2023 at 02:18 pm.

 

[sotxbill]

key could be bad, resistor could be bad, or the connectors involved... And if you measure the coil when the points are closed, it will measure lower pending on which resistor and coil you have... than it will while the points are open... where you will then measure battery voltage. SO if you measure while points are closed, expect it to read much lower... or bump the starter a bit and then remeasure the coil voltage..

 

[Shawnn]

So the limited voltage on the tractors voltmeter is what had me thinking it was the ignition switch. I was able to get one at napa and replaced that and it fired right up! Just seems crazy that it failed spontaneously, is that common? Now I ve replaced almost every ignition related part this year it s crazy!

 

[Sean in PA]

If it starts to run with the key in the "Start" position, and then dies when you let it drop back to the "Run" position,that means that the coil is getting power when t key is in the start position, but it is not getting power when it is in the "Run" position. Check the primary of the coil to see if there are two wires connected to one of the small posts. If so, one is the bypass wire which provides power to the coil when the key switch is in the "Start" position, and the other should provide power when the key is in the "Run" position. Trace both wires. One should go to a post on the solenoid. That one is the bypass wire. The other one should go directly to the "Run" terminal on the key switch. Test that terminal on the key switch to see if it has 12 volts when the key is in the "Run" position. If it does, then check the other end of the wire at the coil to see if it gets 12 volts with the key in the "Run" position.

 

[Tim PloughNman Daley RIP]

First, stop guessing and perform true root cause problem solving methods to troubleshoot any problem. Next, stop buying new parts and replacing until old is tested
and verified good or bad. FACT: 99.98% of all non-starting issues are due to incorrect wiring regardless if using 6V/POS GND or a 12V switcheroo job. Know too many
12V jobs get done incorrectly. As our late friend Dell used to say, ...If your tractor won't start on 6V what makes you think it will on 12V?... Rookie and some
oldie mistakes are they don't understand the OEM 6V system so once a problem arise, think the 'solution' is to switch out to 12V. Wrong. Nothing wrong with 12V just do
it for the right reasons. You must know and understand the 6V system B4 swapping out to 12. The first thing to check when engine cranks but won't fire is the battery.
A good, fully charged 12V battery should measure about 14VDC static. Take it to a good shop and have it tested on their special machine under load. If bad invest in a
good brand; bargain house brands have poor lifespans - 2 years typical. The 2nd major cause of non-starting due to a dead battery is the lack of a fan belt tensioning
bracket on the ALT, or GEN if 6V. Without a belt tensioner, you will never charge the battery. The OEM 6V GEN has one attached to the unit but a 12V ALT will need a
special one as OEM one won't work with an ALT. Not all 12V conversion kits will have one. Next, probing around with your VOM without knowing how and what to check is a
waste of time and you may short out something and cause more problems. You say you replaced some parts with new, mostly tune-up parts, but did you actually set the
timing with a timing light after the points were changed? You just don't put new parts in and be done with it. Get your ESSENTIAL MANUALS and correct documents for a
12V setup - see WIRING PICTOGRAMS by JMOR. Also, many issues are due to incorrect wiring on lighting kits. Up until the 800 lights were never factory installed. I was
always a dealer optional accessory but many fellas try to wire them on their own when switching to 12V and muck it with shorts. Best to start troubleshooting the
wiring by disconnecting the battery then the lighting wiring. There is a lot to the electrical system other than just swapping out the 6V battery to a 12V battery. The
GEN and VR get removed from a 12V circuit altogether. A VOLTMETER just shows VDC on battery - not if battery is actually charging like an AMMETER will. The STARTER
MOTOR uses a 3 Wire unit with a RELAY (SOLENOID). On a 12V setup, you can use a 1-Wire or a 3-Wire ALT. The DELCO 10SI is a 1-Wire unit proven reliable for many. If
staying with the OEM 6V Coil, you will need an external 1-OHM resistor or equivalent in the coil circuit. Swap out with a 12V Coil that meets reduced impedance to 3.0
OHMS and extra resistor not needed. Distributor and timing dont change when doing 12V. Get the ESSENTIAL MANUALS if you dont already have them. You need them for
all the systems beside electrical.

FORD TRACTOR OEM 6V/POS GND SYSTEM:

WIRING PICTOGRAMS by JMOR:

NOTE: WIRING IS SAME FOR LATE 8N EXCEPT USES CCW FIRING ORDER.

AFTERMARKET 1-OHM CERAMIC RESISTOR, USED ONLY IF COIL IS 6V:

FORD TRACTOR ESSENTIAL MANUALS:

Tim Daley(MI)

 

[Shawnn]

(quoted from post at 07:39:38 02/24/23) First, stop guessing and perform true root cause problem solving methods to troubleshoot any problem. Next, stop buying new parts and replacing until old is tested
and verified good or bad.

How is diagnosing with a multimeter and checking voltage at the battery, starter solenoid and ignition switch, guessing? I tested the ignition switch and found it to be faulty... While I appreciate the 6v/12v info, I have already verified my 12v conversion is correct. I recently had to go through the ignition system which led me down the very deep 12v conversion rabbit hole. These forums were very helpful with that! I have the common single wire Delco alternator, starter solenoid, 12v coil with corresponding external resistor, 12v bulbs etc.

My tractor is wired like the "Ford 600 12v conversion, no neutral safety, key start" diagram, except I have a voltmeter as previously stated. Correct me if this doesn't sound right...The wire from the battery terminal on the starter solenoid, instead of going through the ammmeter, to the battery post on ignition switch, goes direct to the battery post on the ignition switch. The voltmeter gets voltage from the ignition post on the ignition switch, which is the same post that sends power to the ignition coil. As previously stated, I only saw voltage on the tractors gauge when cranking, so logic told me the coil wasn't getting power after cranking either. Once I replaced the switch, the voltmeter once again shows voltage with the key turned to run position. The coil should now have power after cranking (key in run position) as it should.

 

[Eman85]

just my opinion but I'd change the tractor back to having a NS switch. Old tractors had no government mandated equipment but even Henry as cheap as he was made a NS standard. There's a good reason for that.

 

[Shawnn]

I definitely agree about the neutral safety switch. I have a list of things I should address this summer when the weather gets nice. I have developed the habit of always making sure it s in neutral before I turn the key and when I park it. This habit carries over from driving a manual car for my entire adult life. But all the same, accidents happen. I also like the idea of the push start.

 

[Lynn Patrick]

Is it safe to assume the ignition switch is bad? .

To answer your question - Yes! Any part can go bad, but ignition switches seem to have a common habit!
I bought an 9N from a small mechanic shop once that he could not get running. He found the bad key switch & replaced it w/a toggle he had. What he didn't check was the toggle switch! I replaced it (w/a key switch & it started right up!

 

[Sean in PA]

Disconnect the wires from the key switch that go to the ignition circuit and to the starter solenoid. Then check the voltage on those two terminals of the switch with the key in the "Start" and "Run" positions. Or remove all wires and test continuity between the terminal that normally gets power directly from the battery to the other two as you move the key between the "Start" and "Run" positions. Those are the two correct ways to test the switch. Testing voltage further down the circuit will not tell you if the problem lies with the switch or a wire in between the switch and where you are testing, it will just tell you whether voltage is getting to that point in the circuit or not, but it will not tell you whether it is the switch or the wire that is bad if voltage is not getting there.

 

[JMOR]

Take a short cut (for switch diagnosis) and jumper across the switch or the terminal block and try to start.