3 terminal ignition

[FirstTractor]

Hi, I have been googling for the past 4 hours and either I am completely inept, or something similar, as I cannot find the answer.

I recently replaced the whole wiring harness on my 460 gas.

I did it exactly according to the wiring diagram.

When I turn the key all the way on (2 clicks clockwise) and press the ignition button, she fires and will run for ad long as I hold down that ignition button. As soon as I let go, it dies.

I began trying to troubleshoot and may have a clue.

The wiring diagram only has 2 posts/wires on the key ignition, however my key ignition has 3 terminals. BAT, and 2 more unlabeled ones, which I m guessing are starter and ignition.

Since the posts are not labeled on either my ignition, or the wiring diagram, I need help figuring out how to fix this please.

Thank you

 

[FirstTractor]

 

[FirstTractor]

 

[FirstTractor]

 

[used red MN]

First..welcome to YT! You need a electrical test meter or test light to check if there is voltage from the black wire
that feeds the resistor by the coil when the key is in the on position. The wire is shown making a connection to
the push button for the starter. Typing this has made me realize the wire must have power or the starter would
not engage. So that leaves checking power across the resistor block to the positive terminal of the coil.
Depending on whether the distributor points are closed or not you should have anywhere from 7 volts to full
battery voltage there with the key switch on. I am guessing you will find the resistor is bad. What is happening is
there is a wire that connects to the starter solenoid which is energized when the starter is engaged. This sends
full battery voltage to the coil to give a hotter spark during cranking. When the starter is disengaged the voltage
to the coil drops down to what the resistor feeds it to help to points last longer and to coil to run cooler. Best of
luck let us know if this helped.

 

[Janicholson]

You may still have an issue with the key. Used Red mn is on to the problem, but lets do a bit of diagnosis.
If the ignition switch is set up with three terminals, and the key does not spring back when turned to the right (which would be a start position like a
car) the terminals are possibly turn left on the key for accessories (all but ignition) center OFF, and right ignition (and accessories at the same
time.
Checking it is easy with the key in the middle position, there should be no voltage on either unmarked terminal. With the key in the right position,
there should be voltage on both, with the key in the left position there should be voltage on only one terminal. If I am right, the accessory terminal
can be left out of your circuit, (the one that turns on when the key is turned left.) Jim

 

[the tractor vet]

If this NEW wiring harness is true to color code , you should have a WHITE wire from the starter solenoid (S) terminal going to the one side of the resistor and onto the coil , you shold have a Black wire going to the other side of the resistor from the ing switch . the black wire should have juice as soon as you turn the key on to the one side of the resistor and feed it with battery voltage , the white wire will supply a shot of 12 volts direct to the points when you press the starter button once you relaese the starter button the 12 volts feeding the resistor should now be gettying somewhere between 6-8 volts coming thru the resistor going to the Coil + side . And orange wire from the starter button should be going to the S side of the starter solenoid

 

[used red MN]

Now that I am up facing a new day with oars in the water I have a simple suggestion that will require no test
equipment. Move the wire from the key switch...shown as black in your diagram...that is on the resistor up by the
coil to the same end as the short wire that goes to the plus terminal of the coil. If the tractor runs as it should
now the resistor is bad. I?m 90 percent certain this is your problem. Running the tractor like this for a few minutes
will hurt nothing. If the wire is to short to reposition simply take an old wire strip off the ends and jump across the
two terminals of the resistor.

 

[used red MN]

Now that I thought about this some more the real question is did the tractor run correctly before you replaced the
wiring? If it did many things I suggested may not apply. In that case you will definitely need some way to test for
power and diagnose the issue. Now that I reread that you Googled for 4 hours I am a little worried you will even
find your way back to this site to see what has been posted. Oh well.

 

[FirstTractor]

Wow you are both great! Thanks for responding so fast and for the welcome. It my first tractor and I m excited to get her going.. Been sitting since 2004. I just rebuilt the carb (it was bad) and put new spark plugs in and put the new wiring harness in (old one was all chewed up). Like I said, fired up but wouldn t stay.

I just went out and checked the ignition with a meter and it seemed fine. I also tried switching the non "bat" wore to the other post and I had the same result.

I just checked the external Coil resistor and found that the small coiled wire inside of it was broken in half.. on my way to go pick up another one right now.

I will report back with the results.

Thank you both again for the help and quick replies!

 

[FirstTractor]

Ok so I guess it was the coil resistor!! Runs like a charm now.. music to my ears.

Thanks everyone again. Starts up on first push of button and stays running at a steady rpm. Time to change the oil.

Have a great day.

 

[used red MN]

Glad we could help. Sorry, for the post where I seemed kind of doubtful of hearing back from you. Many times I
have made similar replies to new posters and never hear back. I just have to accept a lot of folks are expecting
an immediate answer from the internet, which is something you don?t always get here. Happy tractoring!

 

[FirstTractor]

It?s ok haha, I can take some heat, and I can dish it out sometimes too. Thanks again.