Tractor issue

[oldschoolgenz]

I have a 1948 8N and after cranking it, it began to loudly hum or buzz near the battery. It continues making the noise for about a minute and while inspecting the battery I notice the positive cable started smoking. I undid the terminal and as I pulled the terminal off it began to spark, but once the terminal was off the humming stopped. Any ideas on what's happening? It's never done this before.

 

[SheepDog]

You may have a bad post, bad terminal or poor connection.
Any of those is a bomb waiting to go off!

 

[hashbrown]

Sounds like a dead short somewhere in the system

 

[Supervisor42]

Sounds like a dead short somewhere in the system

Starter switch/solenoid is sticking closed.
When the starter continues to run after the engine starts, it makes a loud hum and will overheat the cable.
Unplug the cable with a big spark and it stops after reconnected = solenoid.

 

[Buffalo]

Any time you remove a battery cable, you have the chance of sparks, so you can't really take that as an indicator of much. These older tractors had generators and voltage regulators on them instead of alternators. Our 67 Ford 4000 was having issues with the voltage regulator. There is an electromagnet in it that needs to close in order for the generator to send the correct amount of voltage to the battery to recharge it. When that electromagnet went bad in ours, there would be a buzzing noise from it. If I opened the hood and manually closed the magnet, the buzzing would go away.

From what you are describing, it sounds to me like the voltage regulator may be faulty, causing an overcharge condition, which would overheat the battery cables and the battery.

 

[UrbanHunter]

On an old 8N tractor there should be no current flowing when the switch/key is off. You definitely have a short as @hashbrown and @Supervisor42 indicated.

Based on the amount of current that you are seeing (big spark) I would bet that it is a sticking starter solenoid. To check it, disconnect the battery negative cable, disconnect the big wire from the starter solenoid to the starter (remove it from the solenoid). Now re-reconnect the negative battery cable, try the starter switch, it should click at the solenoid. If you have someone helping you have them hold a voltage tester (or use a volt meter) to the small connection on the solenoid (the wire from the switch to the solenoid), check to see if it comes on when you hit the starter switch and then goes off when you turn it off (if it stays on the starter switch is bad). Do the same thing at the connection that was going to the starter wire, if it stays on after the switch is off the solenoid is sticking closed.... Either way it is less than $25 to replace the defective part....

 

[Aklogcabin]

A short somewhere. On a tractor that old I'd check the voltage regulator. It may be behind the dash panel n hard to get at. It would be energized when the switch is turned on. This tractor probably has a generator to charge the system. When you find it, follow the wire from the generator. Unhook the power wire n test for a spark from cable to battery to analyze or test

 

[oldschoolgenz]

Any time you remove a battery cable, you have the chance of sparks, so you can't really take that as an indicator of much. These older tractors had generators and voltage regulators on them instead of alternators. Our 67 Ford 4000 was having issues with the voltage regulator. There is an electromagnet in it that needs to close in order for the generator to send the correct amount of voltage to the battery to recharge it. When that electromagnet went bad in ours, there would be a buzzing noise from it. If I opened the hood and manually closed the magnet, the buzzing would go away.

From what you are describing, it sounds to me like the voltage regulator may be faulty, causing an overcharge condition, which would overheat the battery cables and the battery.

Mine has 12v conversion

 

[oldschoolgenz]

So I've got it figured out. Humming noise was coming from starter cause it wouldn't stop spinning. Going to have to replace it and the solenoid.

 

[montanabill]

Would love to have me a running 8N.

 

[zoomzoom]

Would love to have me a running 8N.

Haven't checked lately but in my area, you can get them in running condition for $2K and looking/running really nice for around $3K.