I'm working on the above mower with a B&S 16 HP twin model #402707013101 and I can't get the battery to charge. The battery reads 12.7 volts while running but it will decrease as the mower runs.
I've checked all the wiring, made sure that the cables are free of rust but I can't figure out how the battery charges.
I have one green wire coming out from under the flywheel and it shows 12.7 volts. There is another wire coming out from under the flywheel and it goes to the coil which I assume is the ground.
Can someone give me some help as to what to look for?
The battery is new and fully charged and tested and I can find no fuses to check. This is an old mower that a friend got for free.
The stator which charges the battery is located under the flywheel. Please clarify something, you state that you have one green wire come out of the engine. Could this be a green connector with a black wire? Where does this wire go to?
Hate to say it, but I think someone has played with the wiring. With today's engines the only time two wires come from under the flywheel, they should go to the same connector. I don't think I will be able to help you unless you can take the flywheel off and post some pictures. I just won't know what you are seeing. A green wire under the flywheel is not normal and unless I see what your seeing, I don't want to tell you something wrong that could cost you big bucks. Sorry.
After removing the flywheel I found that there was a single black wire coming out of the stator. For some reason the black wire was then shrink wrapped to the green wire. Once it connects to the red wire it then goes to a "module".
There is another wire coming from the same space in the module that the red goes into and it appears to have been cut off. I have no idea where that wire was supposed to go?
I appreciate all the help so far and will continue to try to get this mower charging.
Mike
#8
Grassbandit
when the engine is running the battery is supposed to read something like 14 volts . So I'd say the field coil has stopped functioning and needs to be replaced or you can bypass it by getting a battery tender module and save yourself the hassle.
#9
rmancini
Found this diagram. Don't know if it helps but here it is.
Rich
Did some checking and found that you have a Tri-Circuit Alternator Charging system. I have asked another member to post pictures and a description on how to test the various parts of the system. If he is unable to do so, I will figure out another way to get this info to you. Hang in there and we'll get this solved. Please don't replace any parts until you can test them.
#11
EngineMan
Info ask for....!
Attachments
#12
EngineMan
Going by the colour (green/black/red wire's in post #7) from the stator, it seem's to be the same has L100 so this may help...
My apologies for not getting back sooner. My router got "fried" in a recent thunderstorm. I removed the battery from the tractor after starting it a few times and placed it on my automatic charger over night.
When I came back the next morning it had failed to charge beyond 12.59 volts and the code was telling me the battery got too hot.
According to my manual this might have been caused by a bad cell in the battery. All I have to test the load is an automobile battery load tester so I tried it.
As soon as a load was placed on the battery it showed weak.
Could my problem be a bad battery?
Thanks for all the responses and diagrams. I am printing them out for further reference.
Well I put the new battery in and no change. The electrical system still doesn't charge the battery. I checked the output of the black (from stator) to green to red wire and it was between 15.8 and 16 volts AC.
I will check the red wire going into the module to see if it's the same.
If so would that indicate that the diodes in the module are bad since it appears that there is no DC voltage from there to the battery.
My understanding is the module converts the AC to DC which charges the battery. Is this right?
I will update as to my progress.
I put the meter on AC and with negative lead grounded on the engine and positive lead on the wire from the stator I measured the AC voltage.
Did I do this wrong?
Well I checked the voltage from the stator and it's around 38 volts. This wire then goes into a module that contains four wires. I think this part number is AM 38571. I'm unable to find a way to check this module while the tractor is running since it's located under the battery.
Is it possible that this module takes the place of a rectifier and there is a faulty diode in the module since I can find no regulator/rectifier anywhere?
How can I check this module on the workbench?
That test assumes that the diodes are in a wire. In this case they are in the module which has four pins. I need to know which pins to check such as pin 2 to pin 4. If they were in line this would be easy but they aren't.
Also the 116 has no light circuit since it has no lights so I can't go by that. The module is $45 and maybe it would be just as easy to buy it and hope for the best.
According to the model number you posted and the description you gave of the wires coming from the stator, you unit should not have a voltage regulator. I am at a lose as to what to say or tell you what to do. Can you post any pictures of the components we have been talking about? Also, can you post the exact model number of the tractor?
#26
PJ
Mtn.Mike said:
Well I put the new battery in and no change. The electrical system still doesn't charge the battery. I checked the output of the black (from stator) to green to red wire and it was between 15.8 and 16 volts AC.
I will check the red wire going into the module to see if it's the same.
If so would that indicate that the diodes in the module are bad since it appears that there is no DC voltage from there to the battery.
My understanding is the module converts the AC to DC which charges the battery. Is this right?
I will update as to my progress.
You have to remember that these charging systems are AC voltage. A diode actually synthisizes DC voltage because it only allows currant to flow in one direction. Many times you will have a new battery and it keeps going dead. This is usually due to a bad diode because while it "WILL" charge, but when you shut it off, the bad diode is no longer allowing the currant to flow only one direction, so with engine off, the currant flows "FROM" the battery back to the alternator (like a motor) therefore draining the battery. B & S uses 2 different types of diodes. One is a one wire inline usially red and appears like a bulge in the wire. The other is a 3 or 4 wire module encased in epoxy. This is also a regulator. With a low battery it will allow full charging capacity of the alternator, but as the battery builds up charge, it lowers the output as to not overcharge the battery
I was able to download a pic of the module that I think is causing the problems. The wire from the stator goes to this module.
Even with a charged battery shouldn't the volt meter show that the battery is receiving some charge?
Can you post a picture of the stator. You said that you have wires cut and going nowhere and weird splices. I am wondering if someone changed the stator and tried to use the wrong voltage regulator/module. Just a thought as I said, this one has me really questioning my knowledge.
I put the flywheel back on so no pics of the stator. I can show a pic of the single wire coming out of the stator. It started out as a black wire, then someone used a shrink tube and connected the black wire to the green wire I talked about previously. Then the green wire was connected via a spade connector, to the red wire which goes from the engine to the module previously shown.
I have enclosed a pic of the green wire to red wire via the spade connector.
That is not like any factory set up I have ever seen. Maybe someone else has seen it and can help.
#32
EngineMan
If you have volts going into the box (AC) and none coming out of the box (DC) then replace it. because looking at the photo I don't you taking it apart so easy.
If it is meant to be a rectifier it is wrong if it is meant to be a voltage regulator possible
Rectifier ac to dc 4 diodes two ac inputs an a + plus - output voltage regulator use zener diodes two unregulated volts in and two regulated out as per the drawing on enginemans report
I agree with PJ on how it works, but he only has one AC output from the stator, according to his posts and pictures. That is what does not make sense to me.
I agree with PJ on how it works, but he only has one AC output from the stator, according to his posts and pictures. That is what does not make sense to me.
Well I finally solved the problem. It was the diodes that the stator wire goes into. I got one from John Deere and that fixed the problem and my neighbor is a "happy mower" again.
Thanks to everyone who responded.
Well I finally solved the problem. It was the diodes that the stator wire goes into. I got one from John Deere and that fixed the problem and my neighbor is a "happy mower" again.
Thanks to everyone who responded.
I have the same tractor and I was wondering if I have messed up my stator when I installed it, but didn't put in a new battery right then, I did put a new one in right after I tested the output of the stator
