Electrical problem on a H

[GregtheDC]

My son got an H not long ago, no battery in it. Previous Owner said it was 12v, it had a 12v batt in it. When It made it to my place no battery. Electrical system looks like my Super A, but I don't know if it is a positive or negative ground, how do I tell? Also, I have an older 12v battery that shows 7.78 output with a volt/ohm meter, will this start the tractor. One last question, it does have a hand crank, does it have to have a battery to start even with the crank? Thanks in advance of any and all help
G

 

[w-9 nut head]

Does it have a mag or distributor and next does it have a generator or alternator.

 

[lstra]

Don't think 7.78 volts in a 12 volt battery is going to turn that electric starter motor.

 

[Leroy]

Mag no battery needed, distributor yes battery needed and if it had a
generator probably still 6 volt as 6 volt alternators are very scarce. And
If I rembember correctly it is positive ground but our H was traded off in
1984

 

[55 50 Ron]

If it's still the original 6 volt starter, a true 7.78 volts will turn it. But a 12 volt battery is probably not good if it's that low on open circuit voltage. I wouldn't trust it.

 

[Janicholson]

The H was originally 6 volt positive ground. They operate well that way. But we need to figure out what it currently is setup to operate before giving advice. Many (all of mine but 2) are converted t 12 volts. some using a 12 volt generator and voltage regulator, and some using an Alternator from a car. The generator system has two terminals on the round rear outside of the steel housing. AN alternator is made from aluminum and has one large stud like terminal on the back face of the endframe. If it is aluminum and an alternator, it is 98% probable to be Negative ground. If a generator, and if it has a red identification tag, it is likely 12 volt. If it has a Black tag, it likely is a 6 volt.
A battery does not change voltage unless it is discharged some. When a 12v battery is at 7 or so volts it is effectively dead. Thus it would not turn a starter at all. And if the voltage was read across the battery when trying to operate the starter, it would read near zero volts.
Tell us what you have and if you can take an image of it we can give good solid repair info that will not cause damage. Guess work is not good. To load a digital image from your camera to the computer you use is your call. Reply to this post then attach your picture as follows: at the bottom of this page (scroll down) there is a tag called Choose files. click that tag and find your image in your computer click on that image file and it will load into the post you are making. Jim

 

[GregtheDC]

Thanks to all for the info, I will be looking in the morning when I get back down to the barn. I am pretty sure it is not a magneto, I believe it has a distributor cap facing the rear. I will try to get pics tomorrow as well. I did crank it through a few times with the hand crank and it turns easily.
Thanks again to all, more info in the morning

 

[Janicholson]

Magnetos have a similar cap to a distributor system. the difference is that a magneto has a built in coil on the top that is screwed to the metal of the mag body and distributors have a separate coil 2 inches in diameter in a bracket near or on top of the round distributor body.

 

[GregtheDC]

It looks like a generator, identical to the one on my Super A, also has a coil on top and in front of the distributor cap, also has an oval Delco-Remy tag on the generator (?)

Thanks again, big question is still the type ground but from the info provided by all here I bet it is a neg ground

 

[rustred]

When cranking it over you will hear the impulse tripping in the mag. Plus it has a black cap on the top of it covering the coil inside. And the body is aluminium looking. The battery distributor has the coil bolted on the top of the horizontal distributor. As there is a vertical one also. And if all is still original and it is a distributor , look at the coil wires. Pos ground will have the positive coil side going to dist. Points. And the other way around for neg ground.

 

[rustred]

If u think then the negative on coil will be going to the distributor. Thats how u tell. Plus by the battery cables but that is not accurate.

 

[redforlife]

If it has a magneto (instead of a distributor), it can be started with a hand crank. If it has a magneto, it'll more than likely be an H4 magneto. Google H4 magneto images, and if that looks exactly like what you have, then you'll know.

As for positive or negative ground, that's gonna be hard to guess at with no battery in it. It was positive ground 6v from factory, but that means nothing now unless it has been unchanged. For what it's worth, battery posts are different sizes. One being larger around than the other. You ussually can't switch them around if the clamps were only spread open just enough to get the cable off of the post. This might be a sign as to how it was. But if the clamps were spread open further than needed to remove the cables, this means nothing. As in, either cable will fit on either post. If so, your back to knowing nothing from this.

The original generator, light switch, and so on, would be indicators of an unchanged 6v positive ground system. If you know what those original parts look like.

Pictures of what you have, would be of tremendous help here. Otherwise, we can only give you limited advice.

 

[rustred]

As I said look at the coil hook up its a dead give away as to what ground to use. Simple easy. Its not limited advice its correct advice. As I also said u cant depend on battery cables on a new To u tractor. Plus u could also repolarize the reg. Also.

 

[BarnyardEngineering]

7.78V on a 12V battery is dead beyond dead. There is ZERO energy in that battery. Junk. Good for a core exchange on a new battery or about $15 at the scrapyard. It won't light a flashlight bulb let alone start a tractor.

The electrical system on an H is pretty simple. At this point it's not worth worrying about what you have because it probably doesn't work anyway, and you can't hurt it hooking it up "wrong" even if it does work. If anything, start thinking about how you WANT to have it.

For now a fresh 12V battery and a jumper wire to the ignition coil (assuming it has a distributor) is all you need to make it run. Hook it up positive or negative ground, won't matter. That won't stop it from running.

You don't need a special "tractor battery" by the way. A $65 Walmart "Value" Group 24 battery will work just fine. The batteries are just as good as the high-priced ones, without the worthless warranty.

 

[Heirloom H]

Good advice above. My '45 H is as it was originally, 6 volt, with a magnito, generator, and positive ground. Many years ago I think it quit charging and dad was tired of messing with it, so he began starting it with the hand crank. It started easily that way, first or second crank, so that's how I started it for the 15 years since dad passed. But this year it became stubborn to start so I cleaned and rebuilt the carb(that was the main issue) and replaced the starter, 6v battery, start button, and kill switch. Fires right up with the push of a button now, yay!, but I still need to work out any charging issues. Guage doesnt work, so not sure about the generator or regulator. Until I can address that stuff, I'll just keep the battery on a 6v trickle charger. But it sure is nice not hand cranking it anymore

 

[Heirloom H]

 

[redforlife]

Take it easy rust.

It's possible for the impulse to not trip on a mag. Especially if gummed up, and tractor not ran in years.

Also, my understanding the coil will still work if hooked up backwards (as in previous owner didn't have it hooked up right).

You never know what you might run into. While all advice givin here is good advice, it's still like I already said, going to be limited based on the main post info alone. Nobody gonna be able to say things for sure, without seeing/looking.

 

[rustred]

Greg asked how to to tell what ground you have , so i gave the correct response. you said it will run either way ... yes it could run or may not run and also be hard to start. i have proved all that already in experimenting with old tractors. i have bought tractors with the ground hooked wrong also. example here , the massey 444 had a very weak spark after replacing the points and would not start. i checked the coil hook up and it was wrong for the tractors ground. i then changed the 2 wires on the coil and it fired right up. i cant see his tractors so its up to him to look at the coil's pos. and neg. wires and make sure the pos side is going to the dist as them are pos ground tractors. and from his explanation its has the electric distributor. you only posted your understanding which is not correct to understand it dont matter, yes it matters and i am saying this is a for sure. just like jim says, with out a flame.

 

[Janicholson]

The tag number will identify the voltage if looked up. If it is a 6 volt it needs a 6 volt battery (no matter what was in it, or not, when it arrived. John T is the author of the following steps. TROUBLESHOOTING CHARGING SYSTEMS

ARE YOU SURE THE AMMETER IS WIRED CORRECT AND WORKS????? If you turn the lights or ignition on (if coil ignition not a mag) when shes not running, the ammeter should swing over to the - discharge direction, does yours??? Are BOTH the ammeter terminals reading hot battery voltage?? They MUST !!!!! ! Theres but one wire on the ammeters Supply (from battery/starter) terminal while its other Load terminal wires to the BAT terminal on a Cutout relay or VR PLUS wires to feed loads like lights or ignition, UNLESS where a 4 terminal VR is used, and if so lights n ignition are fed from the LOAD terminal on the VR.

To Polarize the Generator, first temporarily dead ground the Gens Field post to case/frame, then momentarily flash jump a wire from the Cutout Relay or VR's BAT terminal over to its GEN/ ARM) terminal and you ought to get a small spark. Same things accomplished by momentarily flash jumping a hot wire (BAT terminal on Cutout Relay or VR or starter post etc) direct to the Gens ARM post to get the spark.

TROUBLESHOOTING A CHARGING PROBLEM IN CLASS A DELCO TYPE SYSTEMS

1) For a good working Gen to get to and charge the battery, it has to have a path usually from the Gens ARM post,,,,, ,,,,To and through the Cutout Relay (between its GEN and BAT terminals, regardless if on a VR or Relay),,,,, ,,,Up to the Load (NOT to battery) side of the Ammeter,,,,, ,,,To and through the Ammeter,,,,, ,,,,From BAT side of Ammeter to ungrounded battery terminal, often via the starter lug post. Is yours wired that way or equivalent ??? The ammeter should read hot battery voltage on BOTH terminals, does yours??? Even if an ammeter were stuck (but still continuous) as RPM increases the battery voltage should rise from 12.6 to near 14 volts and/or the lights glow brighter (half that on 6 volt systems). Have you tried that in case the ammeter isnt working right?????

2) If the above is so, the BAT terminal on the VR or Cutout Relay MUST ALWAYS READ HOT BATTERY VOLTAGE. Does yours??? If not, the Gen cant get to and charge the battery.

3) The Gen to VR (if it has one) wiring is as follows:

BAT on VR to ammeters load (NOT battery) side

ARM (or GEN) on VR to Gens Armature post.

FLD on VR to Gens Field post.

(L) Load (if you have a 4 wire VR) up to BAT supply input terminal on switch to feed loads like lights and ignition.

WIRING ON CUTOUT RELAYS: They wire BAT side to ammeters Load terminal,,,,, GEN side to gens Armature post. On cutout relay systems, the Gens Field post is wired to the light switch where it gets a dead ground for high charge or a resistive ground for low charge. Therefore, there must be a good connection from the Gens Field post up to the switch PLUS the switch is good and its well grounded !!!!! !!

4. THE GEN AND VR OR CUTOUT RELAY MUST BE WELL GROUNDED AND THE BELT GOOD N TIGHT. If any doubt, run a ground wire from the grounded battery post or clean solid frame member direct to the Gen and see what happens????? ????? ????? ????? ????

NOW, if the Gen and VR are grounded,,,,,all is wired correct,,,,, ,,BAT terminal on VR or Cutout Relay is HOT,,,,, ,,Belt is tight,,,,, ,,,Ammeter is good n continuous n works but she wont charge, have you had the batteries tested lately????? Is there electrolyte above all the plates and no cells have a gray or milky appearance????? A bad battery may not accept a charge you know!!!!! !! If the battery checks okay, proceed below to see if its a Gen or VR problem (AFTER you have insured the wiring per the above)

TO DETERMINE IF ITS A GEN OR VR OR CUTOUT RELAY PROBLEM

5. a) VOLTAGE REGULATOR SYSTEM: With the tractor running, temporarily ground the Gens Field post to case. If she charges then but NOT otherwise, the VR may be bad, or a wires missing from VR's Field post to the Field terminal on the VR, or the VR isnt well grounded.

b) IF ITS A CUTOUT RELAY SYSTEM and she charges only if you dead ground the Field but NOT otherwise, its either a bad switch or the switch isnt well grounded or else the wires bad or open from the Gens Field post up to the switch. INSURE THAT GOOD SWITCH GROUND AND WIRING

6. If she still dont charge, leave the Field grounded and jump a wire across from the VR or Cutout Relays BAT terminal over to its GEN terminal (jump by passes the cutout relay) and see if she charges. If then but not otherwise, a VR's cutout relay isnt working correct (maybe points burned/carboned) or a Cutout Relays NOT working or not wired correct.

7. With the 2 steps above, you have basically by passed the VR or Cutout relays functions, so if she still dont charge, you're left with a bad battery or wiring or the Gen itself.

8. MOTOR TEST. You can Motor test the Gen. If its grounded and you remove the belt and apply hot battery voltage direct to its ARM Post and have the Field Post dead grounded to frame, it should motor n run well (Armature n Brushes and Commutator likely okay). Then, if you next remove the Fields ground and it speeds up some, the Fields probably good. If it passes both those tests, it should charge, and if not, it may be a wiring or battery or grounding problem. The hot battery voltage may be taken off the VR's BAT terminal or the starter post or the battery itself for this test.

9. Typical Gen problems may be the brushes are worn down or the hold down spring assemblies are stuck/corroded/dirty and arent pushing the brushes tight down against the commutator. Check those things out. Worse may be bad fields or armature etc. Air and WD 40 etc can clean and free them, the hold downs must be free n snap and hold the brushes DOWN TIGHT and they cant be worn down too low.

SUMMARY: Check the wiring,,,,,the grounds,,,,, insure BAT on VR or Relay is hot,,,,, ,check battery (maybe load tested and Specific Gravity checked),,,,, ,,,good tight belt,,,,, ,insure ammeter is continuous (BOTH sides HOT),,,,, see if battery voltage rises above 12.6 (half that for 6 volt system) and/or light glow brighter,,,,, ,,,do the Field and cutout relay VR by pass checks,,,,, ,,insure the Gens brushes arent worn down and the hold down springs are free n clean and push the brushes down tight,,,,, ,,,,,check the connections,,,,, ,,,try the Gen Motor Test to see if its good.

You may just have a bad battery or bad ground or connection if the Gen and VR or relay are okay. Good Luck n God Bless, let us all know.

John T Nordhoff in Indiana, retired Electrical Engineer

 

[wore out]

''hard to start'' (with coil polarity reversed)

I don't believe reversed coil polarity has much if any effect at startup.

If it's an issue it will show up as a misfire under acceleration or load, IMHO, especially if the ignition system in marginal to begin with.

Once the sparkplugs are heated up having a negative-going spark at the center electrode gives a more effective spark due to the thermionic emission effect.

''The central electrode is connected to the terminal through an internal wire. The central electrode setup as the cathode from where the electrons are ejected. This is because the central electrode is usually the hottest part of the plug, and thermionic emission principles mean it is easier to eject electrons from a hotter surface.''

Quoted from Wiki.

That being said, many modern engines use a ''waste spark'' ignition system firing half of the sparkplugs with a negative spark and the other half with a positive spark.

The system is designed with enough voltage that there's no misfires from the plugs with the ''wrong'' polarity.