You might need a test lightorammeter here.
red and black means dual-circuit alternator: Black lead is for headlights -- should go to headlight switch, probably through a fuse first. Red is unregulated DC charging. Should lead to ignition and then to battery with key on. You have aproblem here if it is cut: these two wires should terminate in a 2-prong connector and behind that connector there should be a diode encased in the red wire to convert the AC to DC. You will need to replace this or the whole alternator. These alternators are a dime a dozen -- probably easiest to buy a used one and clip off the connector for your use.

The magneto wire should be connected to whatever pole on the ignition switch which is grounded with the key off but not with it on.

Good luck!

 

Yeah, thanks. Here and there guys send me some other info and so far I realized that this is not the right motor under casing with model number. I did some work on cylinder head and found that it doesn't really precised. As well I ordered the carb bowl gasket and it didn't fit at all.

Means I have different motor that doesn't match original tractor wiring.

Alright, I used that pdf with alternators from Briggs site and found that all stators with 2 wires red and black have the same diode. Plus scheme from another pdf with motor replacement give only one solution to rewire.

New plug 393362 plus plug/adapter with diode 393456 from eBay will cost about 30 bucks with shipping to Canada. Just diode in local electronic store is 1.50 (thank Todd for great idea). Today I hardwired, tomorrow I will post the results.

 

Alright, it works. The diode type need to pass current only one direction - from alternator to battery, means any 4A and 12V or whatever available (I could find only 400V) rectifier should be fine. Diode-rectifier. Rectifier - that's the word, cause this thing convert AC to DC. AC from stator to DC to feed the battery. And that's the wire Ammeter sits on.
Good. I've learned something new these days.
I had to rewire all the system to use standard 5-points ignition switch - now head lights are constantly on when in running position. Was it original intention of manufacturer? or to use the 2nd wire from stator on separate switch for the headlights...

 

they would have used a second wire from the stator and run it to a separate switch. Mine has an on-off-on. in the first on position it runs off ac current. that is supposed to be with the engine running. in the second on position it runs off the battery and is to be used when the engine is not running.

 

Wonderful idea! I believe I saw red and green square switches with light when on. I will definitely check today and instal. Nice. Thank you.

 

Here are few pics of my project. All done. Some attributs like stickers or wheel spinner still coming from eBay (how many time I told myself not to buy from China! but **** cheap - spinnner 4.50 with shipping! ok, I pay time for shipping). Anyhow, the tractor was sold on the third day of local advertisement. The guy was happy. And me too. Heh, I got nice buck... and experience not to deal with discontinued product especially when some handy assistant put his assistance into repairs. Like in my case the motor cover was replaced and parts I've ordered were not fitting. I used Tecumseh (you won't believe) to repair Briggs.

 

Nice job:thThumbsU Glad you were able to get the wiring fixed up. $1.50 Radio Shack diode beats the heck out of paying retail for a briggs diode. I have to credit my father in law for that tip, he is an electronics engineer. Be sure to post pics when you get the spinners...Todd

 

" now head lights are constantly on when in running position. "

At least one mfg. that I know of DID have the headlights on whenever the engine was running. Since they ran off AC, made no difference.

ALSO, many mfgs. ran the DC charging wire directly to the battery cable terminal on the starter solenoid, not thru the ignition switch.

Walt Conner

 

Since they ran off AC, made no difference."

Actually, it is convenient to have lights working from the battery and not from the stator. It is handy to turn on lights without turning motor on. Let's say when clean up late at night and have to push the tractor thru the mess in the shed (garage, barn, tent, whatever) these lights are very handy.

If the tractor have no battery, and it is so old that the wires messed up, and it starts from jump start directly to starter or it have no starter and it starts from electric drill... then I bet head light on that tractor quited first.

But for the sake of options, like stlcardinalfan suggested, I made double switch with 2 lights on the dash where one indicates h.lights from startor, another - from battery. Actually h.lights draw so little that 15 amp ammeter feel really lazy about showing discharge.


"ran the DC charging wire directly to the battery"

Actually I was thinking why to use diode to make DC of AC to charge the battery if there is DC one ready.

 

Hi,
Different wrinkle on this same problem so hope you don't mind me not starting a whole new post.

I have a 18hp twin Briggs 407777-0128-E1

I'm connecting to my Ariens EZR 1540. Everything on the charging system seems good except when I turn the key off the motor doesn't kill, rather when the carb is out of gas it turns off.

When I try to connect the wire coming from the magneto then the engine kills.

I think there may have been a diode somewhere in a wiring harness that eventually connected to the key, it may have been cut when the last engine was taken off as the original engine was a 14hp single cylinder briggs.

I've searched the Briggs parts diagrams for this engine and no diode is to be found.

Can someone get me the Briggs part number for this fix or if I buy a diode at Radio shack what Amps, Volts and where do I wire it in?

Thanks
JDK

 

Diode is to convert AC to DC to charge the battery. It allow current to go one way from motor to battery. It have nothing to do with stop the engine. If there is no diode (if it suppose to be) the battery will not charge. That's it.

If the motor does not stop means some ground wire does not ground when the key is in off position. Where do you "try to connect the wire coming from the magneto". The best is to get electrical for the tractor (Ariens EZR 1540).

 

OK, I understand the diode as it relates to the charging system. But on a dual cylinder 18hp Briggs with engine code 407777-0128-E1, what allows both cylinders to turn off when the key is off? There are two armatures and one wire going to the key. If I connect the wire to ground out when key is off then one cylinder quits and other keeps running. If I connect both armatures to the same wire and then run that to the key then they both quit with the key off, but with the key on the engine will turn over but won't catch/run. I was under the impression there was a missing part to the circuit (a diode?) that allows the engine to run with the key on but shorts both cylinders to ground with the key off. I've searched every diagram that Briggs has on this engine and can't see what part I need or what might be missing.

The original engine on this was a single cylinder 15hp so we ran stuck when we put on a dual cylinder as a repower.

Thanks for your help!

 

I believe electric diagram of the tractor should help.

 

OK, here is the electrical schematic on the Ariens 1540. Remember this was a single cylinder system and now we are connecting a dual cylinder. The dual cylinder 18hp Briggs 407777-018-E1 had a bad stator and we put a new one on that had the same type of wiring plug (same color plastic) 2 pin but we can't be sure based on Briggs diagrams which of the 3 styles of stators we need. WE feel we got the correct one as there is some charging.

Here is the electrical for the Ariens as an attachment.

 

If this is the engine I think it is, then each coil/armature has a diode in the grounding wire. If either diode is bad, it will produce the symptoms you are describing. I always replace both diodes so there is no doubt in my mind.....Todd

 

Todd,
Great, I think we are getting closer. I know there is a grounding wire on each side but couldn't tell if the diodes were cut out or are bad.

Do you know if the diodes are visible from the outside of the engine or are under the flywheel?

I can't find them on a parts list for this engine from all the Briggs standard parts pictures. Can you tell me the part number for the diode or do I have to buy a whole new magneto/armature? I looked at the magneto pictures and see no diode as part of the ground wire.

Or, if I can put my own diode in line can someone suggest voltage and amps and I can get one at the local electronics store.

Thanks for your help!
JDK

 

I recently had my magneto kill wire diode fail on a Kohler twin. The old diode was a '1N4002'. Very common diode, 1 amp. I found a 1N4003 in an old LCD monitor and it was close enough that I did not look further. Works great!
Cathode (stripe) goes on the tractor side.
BTW, finding this info in wiring diagrams and parts lists is way too difficult...I have no idea why it should be!

 

Thanks for the info on the do it yourself diode. If someone has a part number that would help as well. Also I assume I can just mount them anywhere inline between the alternator and the where the ground wire connects at the key switch?

Also, I'm studying diagrams for the engine and (although it is not related) I'm wondering if the replacement stator I put in was correct. The standard Briggs diagrams show several style stators. All I know from my tractor is that I have a 2 pin plastic rectangle plug to connect to (not sure if it should be white plastic or yellow)

I found this link to a cub cadet parts list with my same engine code. They list one stator (one with yellow plastic end) and voltage regulator. I'm not sure where the voltage regulator mounts but right now I don't have one. If it mounts on the tractor then my tractor wouldn't have one since it was a 14hp single cylinder at first.

If someone can weight on whether I should replace the stator and voltage regulator and give advice where to install the voltage regulator and which wire goes up to the battery that would be appreciated.

Here is the parts breakout I found:

http://powerparts.homedepot.com/MANUALS/CUB/53AA5A5L100.PDF

see page 28 and items 17 and 24 on the breakout on the next page. I should be putting out more charging amps than I am and I'd like to fix that as well. Although I suspect it has nothing to do with my failure to turn off with the key which probably is the missing diode.

 

I cut the top off of my last diode bag so I don't have the PN but I use a Radio Shack 3 amp 200PIV Epoxy Rectifier diode. Each kill wire will have its own diode, this is what separates them and keeps them from shorting each other out. You will have to remove the shroud to put them in, and it is recommended to pull each armature and do it on the bench. I solder them in and my father in law, who is an electronics engineer, says I don't need to use a heat sink, but I still do as a precaution when soldering.

 

Have you looked at the Briggs Alternator manual?
http://www.tons-of-tools.com/briggswiringexplanation.pdf

Should answer your questions. (But does nothing to tell you about the diodes in the mag kill circuit!!!)

 

Interestingly enough, I'm dealing with the same problem on my wheelhorse(briggs)... I don't want to hijack this thread or move anyone away from this issue, but would somone care to weigh in on this? Check out my last post. I'm out of my range and am flat out confused! I think I'm close to figuring it out, just need a helping hand.

http://www.mytractorforum.com/showthread.php?t=80812&page=3