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8N 12V Battery/Alternator Problems

W

WarnerT

Member
My 8n (with hydraulic issues in a different thread) also has a battery/alternator issues. The details:

Front mount dist w/ 12 v conversion.
Bought new battery, tractor fired up and ran okay for a while, alternator appeared to spin fine.
Tractor restarted a couple times the same afternoon but I parked it and left the key in the on position accidentally.
The key also is stuck in the ignition, not sure if this is relevant.
The next day the battery was dead, only buzzing sound when I try to start. I got it jumped and let it run for 10 minutes or so to try to charge the battery.
I also recharged the battery overnight on trickle while hooked up to tractor. The next day I tried again and there was enough power to start it but carb issues prevented it from staying running. Battery fully dead again after turning starter for 30 seconds or so.

One observation is that after charging the battery all night the alternator was hot to the touch.... which I thought was weird.

Last night I unhooked the battery from the tractor an put it on the charger by itself.

Assuming the wiring is correct, my thoughts are that:

A. The alternator is bad (draining the battery/not charging)
B. The new battery is defective or ruined already (unlikely)
C. There's a short somewhere that's draining the battery while it's hooked up.
D. Nothing is wrong, a combination of leaving the key on, hard starting tractor have led me astray.

Thoughts?
 
(quoted from post at 08:58:38 08/06/14) My 8n (with hydraulic issues in a different thread) also has a battery/alternator issues. The details:

Front mount dist w/ 12 v conversion.
Bought new battery, tractor fired up and ran okay for a while, alternator appeared to spin fine.
Tractor restarted a couple times the same afternoon but I parked it and left the key in the on position accidentally.
The key also is stuck in the ignition, not sure if this is relevant.
The next day the battery was dead, only buzzing sound when I try to start. I got it jumped and let it run for 10 minutes or so to try to charge the battery.
I also recharged the battery overnight on trickle while hooked up to tractor. The next day I tried again and there was enough power to start it but carb issues prevented it from staying running. Battery fully dead again after turning starter for 30 seconds or so.

One observation is that after charging the battery all night the alternator was hot to the touch.... which I thought was weird.

Last night I unhooked the battery from the tractor an put it on the charger by itself.

Assuming the wiring is correct, my thoughts are that:

A. The alternator is bad (draining the battery/not charging)
B. The new battery is defective or ruined already (unlikely)
C. There's a short somewhere that's draining the battery while it's hooked up.
D. Nothing is wrong, a combination of leaving the key on, hard starting tractor have led me astray.

Thoughts?
Click to expand...
One observation is that after charging the battery all night the alternator was hot to the touch.... which I thought was weird." Take alt off & to store for free check........very likely bad.
 
as jmor said if alt was hot to touch after charging. it could be bad... but make sure you are not leaving the #1 wire powered all the time. if so.. it will drain the bat and makie it hot tot he touch after charging all night.
 
What's the #1 wire? Looking at the alternator there are two red wires connected next to one another and a heavier yellow wire off to the side.
 
(quoted from post at 10:53:10 08/06/14) What's the #1 wire? Looking at the alternator there are two red wires connected next to one another and a heavier yellow wire off to the side.
Click to expand...
e assume you have a 10SI.....maybe you don't?
 
there is a spade plug with #1 and #2 #2 loops to charge stud, #1 goes thru a diode or lamp to the key switch.
 
I believe that looks like mine but I can't check right now.

So you're saying that leaving the #1 wire powered (aka, leaving the key turned on) would drain the battery and make the alternator hot?

I'm positive that when I charged it all night the key was "off." Is it possible that the key being stuck in the ignition is an indicator that the ignition switch is bad... and the circuit is staying closed (on) even when the key is "off"?
 
" and the circuit is staying closed (on) even when the key is "off"? "

Just check it w/ a test lamp or a meter.

The switch should have two wires.

Switch off, only one is hot. (battery voltage)

Switch on, both are hot.
75 Tips
 
no need to guess. check it like bruce said.

if both show hot, pull the plug from the alt and recheck. still a chance the alt is just bad.. etc.
 
Okay, batter seems fine. Fully charged at 13+ volts when I got home.

Hooked it up and started checking wires.
With ignition ON: Both #1 and #2 on alternator were hot. Two hot wires coming from switch.
With ignition OFF: Both #1 and #2 wires on alternator were hot. Only one hot wire coming from switch.

Once done checking wires the battery was down around 12.7 volts. Engine fired right up and I ran it for 10-15 minutes. After I checked the battery again - 13+ volts. Makes me think the alternator is working fine.

It appears that the ignition switch is working, and the alternator is working, but something is still draining the battery when the ignition is off. There were 4 wires coming from the switch but didn't have time to draw a diagram and trace all of them last night.

My temporary solution is to unhook the battery when not in use.....
 
Thought I would follow up on this and transfer a question from a different thread.

(quoted from post at 22:52:54 08/15/14)
sounds like your alternator is backfeeding the ignition.

if this is a 3 wire job, what's between the #1 spade terminal ont he al at the ignitionm switch?

should be something like a 168 or 194 bulb
Click to expand...

Yes, it is a 3 wire alternator.

I looked into the wiring to fix the issue above. I didn't have remove too much tape to find that the #1 and #2 wires going into the alternator were just one wire that was split a few inches back. Based on the wiring diagrams I could find, my quick fix was just to run a separate wire straight from the ignition switch to the #1 terminal on the alternator (on the same terminal as the wire running to the distributor). I did notice that it was supposed to have a diode or bulb but I didn't wire one in because A. I didn't have one and B. I didn't know why it was needed.

Soundguy you may be right about backfeeding the ignition, but what is the purpose of the light anyway?

Currently the electrical system seems to be working properly, battery isn't draining, charging when it's supposed to, tractor starts and runs great. The only issue is the key... which is only at non-idle speeds.
 
(quoted from post at 07:58:50 08/18/14) Soundguy you may be right about backfeeding the ignition, but what is the purpose of the light anyway?
Click to expand...

The light (or diode or resistor or ?) is to prevent backfeeding the ignition. If you don't have it, turning the key off won't stop the engine. Power from the alternator will feed into the ignition, keeping it alive and the engine will keep running. 'Course, it's always possible that there is some other strange wiring...

(quoted from post at 07:58:50 08/18/14)
The only issue is the key... which is only at non-idle speeds.
Click to expand...

Not sure what you mean here. Maybe the key won't stop the engine at non-idle speeds? If so, that's the backfeeding problem.
 
This makes some sense. The ignition to distributor wire is going through a resistor (I think) mounted behind the steering wheel. The ignition to #1 plug is not going through that resister.

Sounds like if I spliced the ignition-#1 wire into the ignition-distributor wire AFTER the resistor it should solve the problem?

And yes, the key turns off the engine at idle speed but if the throttle is any faster it won't turn it off. It doesn't really make sense to me.
 
(quoted from post at 11:55:46 08/18/14) This makes some sense. The ignition to distributor wire is going through a resistor (I think) mounted behind the steering wheel. The ignition to #1 plug is not going through that resister.

Sounds like if I spliced the ignition-#1 wire into the ignition-distributor wire AFTER the resistor it should solve the problem?

And yes, the key turns off the engine at idle speed but if the throttle is any faster it won't turn it off. It doesn't really make sense to me.
Click to expand...
ou can try that, but it will not be the solution. Just do it like the diagrams/literature & stop trying to re-invent the wheel. You likely don't understand enough about how these alternators work internally to do that.
 
So that won't be the solution but you don't know what the solution is?

I am trying to follow what the literature says. Not trying to re-invent the wheel. I've seen subtle differences in some of the wiring diagrams I've looked at with regard to the ignition/distributor/alternator. Just trying to work with what I have and get some clarification with how I'm interpreting them... because apparently something isn't quite right.
 
(quoted from post at 08:37:05 08/19/14) So that won't be the solution but you don't know what the solution is?

I am trying to follow what the literature says. Not trying to re-invent the wheel. I've seen subtle differences in some of the wiring diagrams I've looked at with regard to the ignition/distributor/alternator. Just trying to work with what I have and get some clarification with how I'm interpreting them... because apparently something isn't quite right.
Click to expand...
Of course I know what the solution is.........it is the same as myself & others have repeated numerous times. See my post in this thread on AUG 6. If you don't like the idiot light shown, then substitute a diode or a 10 Ohm resistor in its place. Really simple.

or if that isn't clear enough, try this (same thing, different picture):
 
Nevermind what I just posted, I couldn't see that you do have a "diode" note in that diagram.

Hobo - I'm considering just getting a whole new harness/ignition etc and redoing it all but in the mean time I'd like to at least be able kill the engine for nothing other than safety.
 
The reason you switch works at idle and not at higher rpms is that the alternator doesn't work at idle, its not turning fast enough. They make a light that goes on the side of a trailer that works great for the "idiot light". Also, this will let you know if your alt is charging or not. The light comes on with the ign and goes off when your alt starts charging. They're just a few dollars and only takes a min or two to hook up.
 
Here we go again. I'm just finishing up my rebuild/clean out of the hydraulic pump and top cover. Last night I put the top cover back on but I didn't have new oil yet so I decided to fire it up just to make sure it's running well so I can test it once I get the oil in. It's been sitting for a few weeks without running.

It took a bit to get going but it ran fine after a couple minutes. Then it just quit and wouldn't restart. Pulled a plug and tried it again, no spark. I wiggled two wires on the alternator and the one going into the distributor and tried it again, engine fired up on 3 cylinders while I got startled, touched the plug to the engine and shocked my self.

Put the plug back in, it fired right up and sounded great... 15 seconds later - quits again. Then I notice a spark coming from the top of the coil when I wiggle the wire on the coil and also that the ballast resistor is hot with 12v coming in and 12v coming out.... and 12v coming into the coil. I know I didn't leave the key on and I double checked that no voltage is getting to the resistor or the coil with the key off.

Also of note, I replaced the condensor, points, rotor, cap according to Bruce's instructions 3 weeks ago and it ran great. Now after sitting something appears to be messed up between the resistor and the dist.

I really wanted to re-fill my hydro oil tonight and test the rebuild but that won't happen If I can't get it to run. Any help is much appreciated.
 
(quoted from post at 08:41:53 08/29/14) Here we go again. I'm just finishing up my rebuild/clean out of the hydraulic pump and top cover. Last night I put the top cover back on but I didn't have new oil yet so I decided to fire it up just to make sure it's running well so I can test it once I get the oil in. It's been sitting for a few weeks without running.

It took a bit to get going but it ran fine after a couple minutes. Then it just quit and wouldn't restart. Pulled a plug and tried it again, no spark. I wiggled two wires on the alternator and the one going into the distributor and tried it again, engine fired up on 3 cylinders while I got startled, touched the plug to the engine and shocked my self.

Put the plug back in, it fired right up and sounded great... 15 seconds later - quits again. Then I notice a spark coming from the top of the coil when I wiggle the wire on the coil and also that the ballast resistor is hot with 12v coming in and 12v coming out.... and 12v coming into the coil. I know I didn't leave the key on and I double checked that no voltage is getting to the resistor or the coil with the key off.

Also of note, I replaced the condensor, points, rotor, cap according to Bruce's instructions 3 weeks ago and it ran great. Now after sitting something appears to be messed up between the resistor and the dist.

I really wanted to re-fill my hydro oil tonight and test the rebuild but that won't happen If I can't get it to run. Any help is much appreciated.
Click to expand...
f wiggling a wire will make it run or not run, then you need to fix that poor connection. Find & fix.
 
I'm fairly sure that the wire wiggling was just a coincidence. My question is more to do with why the resistor was hot and why it wasn't "resisting" I thought that there should be less than 12v coming out of the resistor to the dist?
 
(quoted from post at 11:32:38 08/29/14) I'm fairly sure that the wire wiggling was just a coincidence. My question is more to do with why the resistor was hot and why it wasn't "resisting" I thought that there should be less than 12v coming out of the resistor to the dist?
Click to expand...
robably a matter of your timing of observation & measurement. A resistor will not get hot without current through it AND if it is a resistor & has current through it, it will get hot AND will be dropping voltage across it. Conversely, if no drop, there will be no current AND no heat. Something not adding up somewhere. Re-measure/observe.
 
Any chance this is related to the backfeed issue from above that I haven't fixed yet? Doesn't seem like it, there's still only one wire coming from ignition, through resistor, to coil. It shouldn't matter if it's being powered by backfed alternator wire or battery, right?

If a resistor is bad will it fail to drop the voltage?
 
(quoted from post at 11:48:50 08/29/14) Any chance this is related to the backfeed issue from above that I haven't fixed yet? Doesn't seem like it, there's still only one wire coming from ignition, through resistor, to coil. It shouldn't matter if it's being powered by backfed alternator wire or battery, right?

If a resistor is bad will it fail to drop the voltage?
Click to expand...

I believe that we do not have any idea how your stuff is wired up, so just about any answers you get will be speculation/guess. Can you draw an accurate diagram of how all wires are connected?

"If a resistor is bad will it fail to drop the voltage?" Only if it has developed a dead short inside & that is highly unlikely.......they usually fail open.
 
(quoted from post at 12:48:50 08/29/14) If a resistor is bad will it fail to drop the voltage?
Click to expand...

Quiet the opposite. They will normally burn and open the circuit similarly to taking a pair of wire snips and snipping a wire in two.

Resistors are very easy to determine if they are open or shorted. Measure the voltage off of each leg as referenced to grd.
 
I drew a picture. I believe the only problem with it currently is that it's lacking a diode between the ignition and 1 terminal on the alternator, I have one I just haven't put it in yet. I don't think that's causing the no spark though.


mvphoto10512.jpg
 
(quoted from post at 13:20:55 08/29/14) I drew a picture. I believe the only problem with it currently is that it's lacking a diode between the ignition and 1 terminal on the alternator, I have one I just haven't put it in yet. I don't think that's causing the no spark though.


mvphoto10512.jpg
Click to expand...
ooks OK. Lack of diode should not result in no spark. To prove it to yourself, just unplug 1,2 connector at alternator.
 
"two wires on the alternator and the one going
into the distributor"

The two on the alternator are not causing no spark
unless they have drained the battery.
That one on the coil is a definite possibility.
I would make sure that connection is clean and
tight.

I'm not that far from you, if you want a hand with
it send me
an email and I'd be happy to stop over and see if
I can help.
I can't do it tomorrow, but maybe Sunday afternoon
or Monday.
Always nice to meet fellow Ford fans.
 
Thanks Royse, I might take you up on that some time.

Follow up on this. On Friday I took the coil off and checked the connections. Put it back on and made sure the wire going in was clean w/ good connection. This seemed to work. It fired up and ran well. I also installed the diode and replaced the ignition. Over the weekend I got the hydraulics re-assembled and I was able to start the engine 4-6 times on the first try, no issues. I even hauled some wood with a trailer back and forth across the yard. It seemed fine but I never ran it for more than 10-15 minutes at one time.... and never above 2nd gear.

Last night I decided to take it for a little drive back to the woods and I made it 200 yards in 3rd gear and it quit on me.... didn't have any tools to check the spark but I'm confident that was the issue. I let it sit for 5-10 minutes, it fired up and I made it far enough to turn around and it quit again. I waited a little longer and tried it some more before I got frustrated and towed it back.

Not sure what the deal is... I replaced the ignition because I was actually getting some voltage through the switch with the key off, less than 1v. I thought I'd try it since I had a new one. Would a bad coil have these symptoms?
 
Since no one responded on this I'll just keep responding to myself...

After sitting all day it fired up great again last night.... I drove it to the end of the driveway and it died again.

Earlier on in this thread I asked about a bad resistor and I was told that they normally would fail open and not allow voltage through. I looked at mine last night, and it looks like this:
mvphoto10667.jpg


I would assume the white strand is supposed to be connected.... What's really ironic is that I just so happen to have a 2N I'm trying to sell with a 12v conversion also (long story). I thought I'd swap the good resistor to the 8n and see if it fixes the issue. To my dismay, the resistor on the 2N is broken too. The 2N runs great, I used it to tow the 8N back to the barn. I think I'm getting power to both dist through the spring holding the white strand, for some reason the 2N doesn't care but the 8N does?

So both tractors fire up with a broken resistor, one runs fine, the other seems to lose spark after it's "warmed up" I'm going to replace the resistor(s) but this isn't quite adding up.
 
(quoted from post at 08:28:12 09/03/14) Since no one responded on this I'll just keep responding to myself...

After sitting all day it fired up great again last night.... I drove it to the end of the driveway and it died again.

Earlier on in this thread I asked about a bad resistor and I was told that they normally would fail open and not allow voltage through. I looked at mine last night, and it looks like this:
mvphoto10667.jpg


I would assume the white strand is supposed to be connected.... What's really ironic is that I just so happen to have a 2N I'm trying to sell with a 12v conversion also (long story). I thought I'd swap the good resistor to the 8n and see if it fixes the issue. To my dismay, the resistor on the 2N is broken too. The 2N runs great, I used it to tow the 8N back to the barn. I think I'm getting power to both dist through the spring holding the white strand, for some reason the 2N doesn't care but the 8N does?

So both tractors fire up with a broken resistor, one runs fine, the other seems to lose spark after it's "warmed up" I'm going to replace the resistor(s) but this isn't quite adding up.
Click to expand...
nowing this little fact will make "adding up" a little easier for you. The "spring" as you call it IS the resistive element (specific wire characteristics). The white center is merely an insulating form on which to wind the wire.
 
That makes more sense.... but it rules out the resistor as the issue.

But still doesn't explain the problem I'm having with the engine quitting. I even swapped coils with the 2N and it did the same thing - which leads me to believe it's not the coil.

I'm out of ideas other than to take apart the distributor again, which I just did a month ago. It doesn't seem like the points would be the issue if I'm only having issues after it's run for a bit.

Is there anything else on an 8N that would stop working properly after warming up?
 

If you throw an OHM meter across that resistor, what reading do you get? What do you get when the tractor cuts out?

Sounds like you have a heat issue. Meaning when one of your electrical components heats up, it creates an open circuit not allowing current to flow.
 
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