parasitic draw

Hi, I just acquired a 1951 Ford 8N and discovered a parasitic draw. The last owner just kept disconnecting the battery to keep it from draining. Now notice it's connected negative ground. Could that be the "grounds" of my problem. Yes, pun intended. It should be positive ground, correct?
Thanks,
Steve AKA Ordinaryguy.

First, has it been converted to 12 volt? If so it would most likely be neg ground, but not always. Does it have a generator or alternator?

Hello Ordinary welcome to YT! First get an
exterminator to get rid of them parasites.. ha ha! I
suspect the tractor has been converted to 12 volts and
likely has an alternator installed. My guess is it was not
wired correctly. Is there any identifying writing or the
like so we can determine what it is then we can sort
out how it should be wired and if it is. Essentially the
grounding has nothing to do with your problem. By
chance was a volt meter installed on it? If it has been
and it always reads voltage that is one of you
problems. It should be wired into the ignition so it only
shows voltage when the key is on. You could post a
picture of it using the ..Choose files.. button down
lower on the reply page. You will have to post from
..Modern View.. the post count to allow photos on
Classic is still 5, on Modern it is one.

Nope, It's still 6 volt. Sorry I didn't include that info.

Even 6 volt systems can be converted to alternators. Testing requires a test light (Common auto store device for 6 or 12v) With the battery disconnected, make sure the drain is real by connecting the test lead clip to the battery clamp that is disconnected, then touching the open battery post. If it lights, there is a substantial draw. Next reconnect the battery and find the starter relay (solenoid) the big cable attaches to one big stud, the other attaches to the starter motor. a third wire is from the start button (through safety switches usually) leave this alone as it likely is not an issue. The stud with the big wire from the battery also has a smaller but fairly big wire going up into the dash. disconnect this wire and see if it lights the light when connecting from the big cable to the terminal on the disconnected wire. if it does, the draw is being followed correctly. this same process is followed (disconnecting the end, and checking to where it was connected) until you find the thing that is making the draw. Likely things are a stuck voltage regulator, or wire rubbed through insulation, or a light that is staying on. Jim

If alternator (usually aluminum and as wide as tall) it could be wired with no diode or light in the exciter wire to shut it off.
If generator, there are

Tractor will run on POS or NEG system. 99.98% of all non-starting issues are due to incorrect wiring regardless if 6V or 12V; it's how they are wired. Don't assume
just because you have a 6V battery the rest of your system is set up for the 6V/POS GRN system. A '51 would indicate a late 8N using the Angle (Side) Mount Distributor
and that is more important than worrying about a model year. You need our ESSENTIAL MANUALS and related documents from JMOR on wiring. Go thru entire wiring using
documents and your VOM set to Continuity, NOT an Idiot Test Light. First, pull battery, take to a reliable shop and have tested on their machine under load. Your
basic garage/shop trickle charger is not going to do anything especially if you've overcharged the battery and boiled the electrolyte out. You can't replace it; it
doesn't work that way. With battery removed, motor test the GEN. It is a 3-Wire/2-Brush 20A Unit and it MUST have a fan belt tensioner attached otherwise you will
never charge the battery. The GEN also requires the Voltage Regulator. GEN & VR wires are ARM BAT FLD. Get them right. Starter Motor is a 3-Wire Unit that uses a Relay
(Solenoid). I&T Manual has a motoring test. If good, after all wiring is verified correct, connect battery and Polarize GEN via VR. Once running again, invest in a
float charger - DELTRAN BATTERY TENDER JR is good and keep battery in charge when tractor not in use. Start here...

FORD 8N TRACTOR - 48-52; FRONT & ANGLE MOUNT DISTRIBUTOR:




FORD 8N TRACTOR ESSENTIAL PARTS & SERVICE MANUALS:


Tim Daley(MI)

Ground does not matter to the old style generator and electro-mechanical voltage regulator, as long as things are consistent.

Swap the battery cables, swap the wires on the ammeter, polarize the generator, and you've changed "ground."

There isn't much on an 8N to cause a parasitic draw. The headlights are on, the regulator is stuck, or a wire has rubbed off and is shorting out somewhere.

Negative ground is likely not your problem. It was factory ORIGINAL postive ground. Negative ground is CORRECT if properly configured.

For negative ground - post on coil goes to side of distributor. Connect ammeter to show negative with switch/lights on, engine not running. Some generator regulators are marked positive ground, some negative ground, some either polarity.

You regulator would be determining factor in proper polarity configuration.

First thing I would check for parasitic draw is to see if the cut out contacts in your regulator are stuck closed.

Remove the ground wire.
Install an ammeter between the negative post on the battery and
ground.
Then start disconnecting one wire at a time until the ammeter
shows zero amp draw. Good chance voltage regulators are prime
suspects.
Don't try to start the tractor. Most cheapie ammeters on EVOMS
measure 10 amps max.

The first thing to check is the regulator, good chance the cut out relay contacts are welded.

If the polarity was reversed, who knows what has been done, it could have overloaded the regulator
trying to charge the battery in reverse polarity, it could have been jumped from a 12v, (never do that
BTW) anything is possible.

If disconnecting the regulator removes the drain, then the regulator is the problem. Best to put it back
to positive ground AND POLARIZE THE GENERATOR BEFORE STARTING IT! Regulators are somewhat polarity
sensitive, has to do with the alloys in the contacts.

Other places to look if the regulator is not the problem would be the ignition switch, light switch,
corrosion growing across a connection, especially anywhere that gets wet.

(quoted from post at 16:47:50 12/19/22) The first thing to check is the regulator, good chance the cut out relay contacts are welded.

If the polarity was reversed, who knows what has been done, it could have overloaded the regulator
trying to charge the battery in reverse polarity, it could have been jumped from a 12v, (never do that
BTW) anything is possible.

If disconnecting the regulator removes the drain, then the regulator is the problem. Best to put it back
to positive ground AND POLARIZE THE GENERATOR BEFORE STARTING IT! Regulators are somewhat polarity
sensitive, has to do with the alloys in the contacts.

Other places to look if the regulator is not the problem would be the ignition switch, light switch,
corrosion growing across a connection, especially anywhere that gets wet.

Click to expand...

esides all the other 'hints', if battery is charged and the draw is going on for several minutes, feel the generator....if warm, then VR cut out contacts are stuck closed. No tools, meters, wires or even electrical knowledge needed.

Check the regulator and go from there

If if has an amp gauge, disconnect it. I've seen them draw down battery's over night.