melting wires?

[rovert21 5]

Ok, so I have a 314-8 tractor that I acquired a few years ago and finally starting to work on it. Since I've owned the tractor it has never started with the key, only buy jumping across the solenoid. I've come to realize that one of the terminals on the ignition either burnt off or rusted off, so I got a used one and installed it. I also replaced the starter solenoid as it has deteriorated from starting with screwdriver. I put on the new parts excited to finally start this thing with a key, but when I turn the key I get smoke. The ground wire going from the ignition switch to the chassis ground melted. What would cause this? I know there could be a lot of variables, but electricity is like voodoo to me so I'm looking for some help. Could the ignition switch I got be internally shorted, or could it be the wrong one. Could the solenoid be the wrong one or defective? I've attached a picture of the wiring diagram for the tractor.

[ZXT 2,401]

Look on the back of each of the switches and see if the pin out is the same. I'd almost bet that you have a different part # switch that uses the same connector but has the wires located differently. 

 

Looking at the diagram you posted, assuming it is for your tractor shows that you have a "M" post on your ignition switch, since it has a magneto. I'm going to guess that the switch you installed has an "I" instead, which is for a battery ignition tractor. 

 

Do you know what year the tractor is? That would help in identifying which switch you need.

Edited June 13, 2019 by ZXT

[ebinmaine 67,628]

 

Wrong switch would be my first guess as well.

 

Don't be afraid of wiring. Electricity moves alot like water. You just need the right switches instead of valves.

 

If you could post your tractor's numbers @gwest_ca or others could get you the correct verified schematic.

 

Also a few pics would help us see what you see.

 

 

[953 nut 55,321]

Sorry to hear about your problem, but you have come to the right place. The ignition switch for your 314-8 would be part number 103 991 and can be found on or places like tractor supply. I hope that the coil on your engine didn't get hit with 12 volts because that will tend to damage them.. There is a four wire plug going to your engine, two wires (orange and tan) go to the oil level switch, blue to the mag. and white/purple to the charging system. Disconnect this plug and use a timing light if you have one or remove the spark plug and with the wire attached lay it on the head to see if you have spark when the engine is cranked over. If you do have spark then say a little prayer of thanksgiving. If there is no spark then more testing is needed.

This service manual should be helpful.

 

[adsm08 2,069]

8 hours ago, rovert21 said:

Ok, so I have a 314-8 tractor that I acquired a few years ago and finally starting to work on it. Since I've owned the tractor it has never started with the key, only buy jumping across the solenoid. I've come to realize that one of the terminals on the ignition either burnt off or rusted off, so I got a used one and installed it. I also replaced the starter solenoid as it has deteriorated from starting with screwdriver. I put on the new parts excited to finally start this thing with a key, but when I turn the key I get smoke. The ground wire going from the ignition switch to the chassis ground melted. What would cause this? I know there could be a lot of variables, but electricity is like voodoo to me so I'm looking for some help. Could the ignition switch I got be internally shorted, or could it be the wrong one. Could the solenoid be the wrong one or defective? I've attached a picture of the wiring diagram for the tractor.

 

 

You almost have to have the wrong switch. A ground wire should never melt, and if it did that means that something connected it directly to the battery + without any load in the circuit. Basically when you flipped the switch it grounded the battery's positive terminal.

 

 

2 hours ago, ebinmaine said:

 

 

Don't be afraid of wiring. Electricity moves alot like water. You just need the right switches instead of valves.

 

 

 

I love using the water analogy. On TRS I spend a lot of time explaining to plumbers how to look at their electrical issues because they are confused by the voodoo electricity. I lay the circuit, and what it is doing out for them with plumbing terms and suddenly they get it.

[ebinmaine 67,628]

5 minutes ago, adsm08 said:

love using the water analogy

it's been quite a good many years since it was explained to me that way. I wish I could remember who it was and I would be very happy to give them credit for such a great way to put things plain and easy.

[adsm08 2,069]

47 minutes ago, ebinmaine said:

it's been quite a good many years since it was explained to me that way. I wish I could remember who it was and I would be very happy to give them credit for such a great way to put things plain and easy.

 

I know exactly who first used that analogy with me. It was my auto tech prof John Cuprisin. He told us that electricity is like water in a pipe. Voltage is the pressure, amperage is the volume, 

 

UTI/Ford instructor Mark Winther explained parallel resistors like a toll booth on the turn pike. The road an only handle so many cars but the stack up at the toll booth is going to be determined by how many lanes there are.

[rovert21 5]

Ok. Thats kind of what i was thinking either wrong or bad ignition switch. I can post numbers when i get home. Hopefully i didnt screw anything else up. 

[rovert21 5]

[rovert21 5]

This is the used switch i tried to use 103990. I see no legible numbers on original.

[ebinmaine 67,628]

9 hours ago, 953 nut said:

ignition switch for your 314-8 would be part number 103 991

Mystery solved.

 

 

Incorrect switch.

[adsm08 2,069]

Make sure you repair that melted ground before trying to fire it up with the right switch. IIRC the magneto systems shut down by grounding everything, causing power loss to the ignition system. Without that ground the engine can't shut off.

[ebinmaine 67,628]

1 minute ago, adsm08 said:

Make sure you repair that melted ground before trying to fire it up with the right switch. IIRC the magneto systems shut down by grounding everything, causing power loss to the ignition system. Without that ground the engine can't shut off.

I would add to that good bit of information by reminding you that if electricity can find a path, it will. If you don't have a large enough ground but you do have a small one elsewhere, you'll send a bunch of current through the small one and melt it. Ask me how I know...

 

[adsm08 2,069]

25 minutes ago, ebinmaine said:

I would add to that good bit of information by reminding you that if electricity can find a path, it will. If you don't have a large enough ground but you do have a small one elsewhere, you'll send a bunch of current through the small one and melt it. Ask me how I know...

 

 

Sometimes even where there isn't supposed to be one:

 

[ebinmaine 67,628]

1 minute ago, adsm08 said:

 

Sometimes even where there isn't supposed to be one:

 

Ouch!!!

[adsm08 2,069]

57 minutes ago, ebinmaine said:

Ouch!!!

 

Meh, took more time to find my wire working multi-tool than it did to fix.

 

I routed the throttle cable wrong while messing with it last week, it pushed one of those wires up against the regulator bolt there, and it rubbed while mowing. I lost the wires to and from the amp meter, and the power wire to the lighter socket.

[rovert21 5]

Thanks, looks like I will be getting a new switch, never would have thought there were different ones. Hopefully everything else is ok.

[gwest_ca-(File Mod) 11,047]

Here is the required switch. Click on the picture and on the pictures on the next page. Describes how to check the switch.

Garry

[squonk 41,155]

A bad main ground will definitely cause a small ground to melt. Had it happen to me on an 80's Chevy truck. Main ground was broken and all the starter current went thru the body ground.

 

On a brand new Olds with a manual trans. A loose ground caused a clutch cable that was next to it act as the ground and melted the cable! 

 

When you replace that switch double check your ground.

[adsm08 2,069]

1 hour ago, squonk said:

When you replace that switch double check your ground.

 

And add a few more while you are at it.

 

On a 12V DC system, you basically can't over-ground stuff.

[rovert21 5]

Ok. so who is good with wiring diagrams? I have the correct switch now so i think, as its not melting the ground anymore. 103 991 does not appear to be the right switch as mentioned ablove. 116338 I believe is the correct switch and the one im using now. The wiring on this tractor was pretty bad so i decided to delete the oil level saftey and realy, and the indicator light module, this is where my current problem is. Any place 2 wires went to same terminal on light module i simply cut them and reconnected them. Any place there was only one wire I cut and capped wire. Now im not good with this stuff and i think were I messed up was with the oil sensor and relay. I took the tan wire from the ignition switch that went to oil level sensor, and the tan wire that goes to the pto switch from connection 4b on schematic and tied them to the 2 black wires form connection 1b were old relay would have been. I took the light blue from connection 11 to purple 17a. I did that to bypass the oil sensor and its relay. I am now melting the tan wire from the ignition switch that used to go to oil level sensor. Can someone explain how the old circuit worked and what I did wrong. 

[gwest_ca-(File Mod) 11,047]

Do you have these detailed wiring diagrams?

The tan wire carries power so connecting it to a black which is ground creates a short.

 

The low oil switch is not shown but the relay is. That is how the relay would be with the switch not connected or the oil level OK = float not activated

Just unplugging the low oil switch should allow the starter circuit to work. Under low oil conditions it opens the relay so it won't start.

 

The light panel can just be unplugged and it will have no effect on the rest of the system. When working it just monitors the safety switches to show you which one is causing a problem.

 

If you need to remove the low oil switch there are instruction on how to do so without damaging the switch. They are no longer available from Kohler.

 

Garry