Wires started smoking today

[ddelarosa74868]

I have an old 80's L235. Never had a problem in the 15 years I've owned it, until today. I noticed smoke coming from the wires that are plugged into the regulator today. Havent had time to look very close at what was going in since it happened right before dark. But, I did see that a few wires melted the insulation off. My question is, do I even need the regulator. I'm thinking of stripping all the wiring off cause none of the lights work and the clutch safety switch is bypassed anyways. All I want is the key and glow plugs.

 

[Russell King]

You could probably eliminate the alternator and regulator if you want to charge the battery in other ways when the tractor is parked, or have a remote (separate from tractor) battery used just to start the tractor.

The tractor will run without the key on so the alternator is not functioning then.

You can easily replace the harness, alternator and regulator for $$$, or repair it for $$

 

[Motion]

I'd recommend first disconnecting the battery. Yes you can run a striped down version. The wires melted due to a short or major overload. Did any fuses blow? Separate the affected wires to determine the extent of the damage, if not too bad then can be reinsulated with shrink tube and crimp connectors, be sure to use adhesive lined. Ensure that the ground from the battery to the frame is super clean and in good condition especially if it's the woven brass flat type, corrosion can get into the pressed connector on the battery post side and affect the current carrying capability. Good luck

 

[GreensvilleJay]

Haven't seen the wiring diagram, but ca I have to assume there's some kind of electrical solenoid to shut off the fuel ? If so, you could be 'at the back 40', batteyr dies just enough to kill engine, and now, NOT enough electrons restart. That'd make for a LONG walk back to the barn to get a good battery, jumpers and anothe rLONG , tiring walk to get back to the tractor !
It all depends upon your normal use of the tractor.
If you decide to just disconnect the alternator, consider carrying a portable 'battery pack', that way, you'll never have to walk home.......

 

[Dave_eng]

Haven't seen the wiring diagram, but ca I have to assume there's some kind of electrical solenoid to shut off the fuel ? If so, you could be 'at the back 40', batteyr dies just enough to kill engine, and now, NOT enough electrons restart. That'd make for a LONG walk back to the barn to get a good battery, jumpers and anothe rLONG , tiring walk to get back to the tractor !
It all depends upon your normal use of the tractor.
If you decide to just disconnect the alternator, consider carrying a portable 'battery pack', that way, you'll never have to walk home.......

I do not see any electrical stop solenoid on the L235 wiring diagram.

Dave

 

[Motion]

The diagram doesn't show a solenoid If it shuts down when you turn the key off, you have a solenoid. Before this event when you wanted to shut the engine down did you pull a red knob rod out (manual fuel cutoff) and turn the key off?

 

[ddelarosa74868]

I'd recommend first disconnecting the battery. Yes you can run a striped down version. The wires melted due to a short or major overload. Did any fuses blow? Separate the affected wires to determine the extent of the damage, if not too bad then can be reinsulated with shrink tube and crimp connectors, be sure to use adhesive lined. Ensure that the ground from the battery to the frame is super clean and in good condition especially if it's the woven brass flat type, corrosion can get into the pressed connector on the battery post side and affect the current carrying capability. Good luck

You think it could be a faulty regulator? Could I strip down the tractor and put an Autozone regulator on it just for the alternator?

 

[Motion]

As always do as you feel is best. It could possibly be the regulator. Charging systems that use regulators in my opinion are always problematic. I prefer an alternator with the built in diode. Not knowing what use you have for your tractor, if you have an immediate need to use it, then separate the affected wires, start the tractor and disconnect the battery and go about your work. I not keen on "striping" especially when it comes to safeties. At the next opportunity hopefully under a shed go through the entire electrical system, clean connections, connectors, all grounds, fuses, etc.. Wires that are still in coverings should be ohm to ensure condition. This may seem to be a waste of time but after 30 + years of dirt, dust, vibration, it deserves a little attention. If a manual is available it should contain a troubleshooting guide for the charging system. If you decide to convert I'd just go with an alternator without a regulator. Again check both ends of the main ground. Good luck

 

[Donystoy]

You are going to have to find the location of the short to ground. Yes it could be within the regulator itself but I have never seen or heard of that happening. Likely a wire has had the insulation compromised somewhere allowing the wire to contact the steel of the tractor. And yes almost any regulator will work if you know how to hook it up. I would certainly not try to eliminate the regulator as someday you are going to sell this tractor and no one will give you the value if they have to start it with a battery or battery pack. You could start it that way in the interim for yourself until you get it properly repaired as you do not use any power once the tractor is started. You likely have a manual lever for shutting the engine off as I do and of course will not have any functioning lights.

 

[Dave_eng]

The old regulators are mechanical types with coils and contact points like an old style ignition system. When the points stick closed you can see overloads occurring. If the regulator has a black metal cap held on by two screws odds are it is a mechanical type.

The main output from the 10 amp alternator is direct to the battery. The internal diodes stop the battery from discharging back into the alternator so if the smoking wires are at the regulator, the main diodes are OK.

Many owners replace the original charging system with a Denso one wire alternator with 40 amp output which eliminates an external regulator and is easy to connect.

Look at post #16 in the following thread.

Desno


Dave


The two Unit regulator assembly controls maximum output voltage and the
switch operating the "charge indicator"
lamp. Control of reverse current flow
through alternator with engine not running
is accomplished by alternator
diodes and control of maximum current
output is accomplished by alternator
design.
When ignition switch (IG-Fig. 76) is
closed, current from battery flows
through indicator lamp (L) and "L" terminal
on regulator, through one set of
closed points to grounded (E) terminal,
causing lamp to light. Current also flows
through "IG" terminal on regulator,
through other set of points, then
through "F" terminals on regulator and
alternator to energize alternator field
coils.
When engine is started and alternator
commences to charge, main current flow
is from the "B" terminal on alternator
direct to battery. A second minor charging
current flows through the "N" terminals
on alternator and regulator
where it energizes the indicator lamp
relay winding, opening points in indicator
lamp circuit and closing points to voltage
control relay shunt windings.
When battery is fully charged and
alternator output voltage rises above
regulator setting (which should be
13.6-14.6 volts), current in voltage control
relay windings opens upper set of
points in voltage control unit. Field current
from battery must then flow
through built-in resistor in regulator and
charging rate is reduced. In actual operation,
points oscillate rapidly between
closed (upper) setting and open (resistor)
setting at slower operating speeds; and
between open (resistor) setting and
lower (grounded) point at higher
operating speeds.
Rated output should be 10 amperes
and regulated voltage should be
13.6-14.6 volts.
84. OVERHAUL. Refer to Fig. 77 for
an exploded view of alternator unit.
Renew brushes if worn to scribe line and
brush springs if heat damaged. Only the
brushes and springs are available separately;
if any other damage is present,
renew alternator assembly.
85. REGULATOR. Voltage regulator
is available only as an assembly and
adjustment is not normally required.


Output voltage is controlled at 13.6-14.6
volts, with a rated output of 10 amperes.
With wiring disconnected or regulator
removed, check alternator using an
ohmmeter as follows:
Touch ohmmeter leads to "IG" and "F"
terminals of regulator. Ohmmeter
should read zero. If cover is removed
and upper voltage control points
manually opened, 11 ohms resistance
should exist across resistor.
Touch ohmmeter leads to "L" and "E"
terminals of regulator. Ohmmeter
should read zero. If cover is removed
and light relay points opened, 100 ohms
resistance should exist across voltage
regulator coil.
Touch ohmmeter leads to '*N" and "E"
terminals of regulator. Reading should
be approximately 23 ohms.
Infinite resistance should exist between
"B" terminal and any other terminal
unless regulator cover is removed
and light relay armature pushed down to
connect lower set of points. With armature
depressed, zero resistance
should exist between "L" and "B" terminals
and 100 ohms resistance should
exist between "E" and "B" terminals.

 

[GeoHorn]

Find the ”short”. (Mouse-eaten wire or wire-insulation damaged by abrasion/rubbing... and fix it properly (which is with genuine Kubota parts. The original design has lasted.... how long has it been..... ??.... what?.... Forty-Years...??

 

[Donystoy]

When the contacts of the old mechanical regulators stick they supply an over voltage to the battery and boils them dry. Did a nut and bolt restoration on an old car and soon after the regulator stuck. Ended up having paint and plating damage from the boiling acid coming out of the battery.

 

[GeoHorn]

When the contacts of the old mechanical regulators stick they supply an over voltage to the battery and boils them dry. Did a nut and bolt restoration on an old car and soon after the regulator stuck. Ended up having paint and plating damage from the boiling acid coming out of the battery.

That is only one mode of failure of a vibrating-points regulator. Other modes are: fail to charge, and under-charge. The most common is “fail to charge” due to loss of polarity. Simple fix...but not germane to this thread.
I like old vibrating points regulators because they are dirt-simple-easy to fix and cheap to replace... as opposed to solid state or internal types which are a mystery ...external ones are expensive and internal ones above the typical owners’ ability.

Do NOT follow the advice above about disconnecting the battery if your alternator works at all...because you will expose it to possible runaway-voltage. The battery acts as a huge capacitor / electric shock-absorber and must remain in the circuit.

If you give up completely on the OEM repair-scheme.... you might consider a Delco single-wire S-10 alternator which has an internal regulator. They are very affordable and reliable....having been used for decades in 1960s thru 1990s GM cares/trucks.

 

[ddelarosa74868]

Thanks for all the replies. This is the best forum! I told my wife's uncle what happened and how I wanted to strip it down. He said absolutely not and to bring it to him. He dug into it and found it was the thermal flasher! He disconnected it and repaired the melted wires. Been running it all day without a problem. I would have never even thought to look at that.

 

[Old_Paint]

As always do as you feel is best. It could possibly be the regulator. Charging systems that use regulators in my opinion are always problematic. I prefer an alternator with the built in diode. Not knowing what use you have for your tractor, if you have an immediate need to use it, then separate the affected wires, start the tractor and disconnect the battery and go about your work. I not keen on "striping" especially when it comes to safeties. At the next opportunity hopefully under a shed go through the entire electrical system, clean connections, connectors, all grounds, fuses, etc.. Wires that are still in coverings should be ohm to ensure condition. This may seem to be a waste of time but after 30 + years of dirt, dust, vibration, it deserves a little attention. If a manual is available it should contain a troubleshooting guide for the charging system. If you decide to convert I'd just go with an alternator without a regulator. Again check both ends of the main ground. Good luck

There's more than just a diode in alternators that don't require external regulators. There are in fact at least three diodes, if not 6, but they may be in a single module. There's a regulator in there too. Without a regulator, the alternator will boil a battery dry with overcharging. There's just fewer wires to connect because all the stuff is in one place. But they work exactly the same way. External regulators went the way of the dodo on cars a long time ago. Something has to turn back the excitation on the alternator rotor when charging is not needed. While more convenient for wiring, alternators with internal regulators can be a little more pricey to repair. It's usually more cost efficient and faster to pop the old one off and a new one on.