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My wiring situation on my 1996 Craftman with a Briggs and Stratton motor (287707 1255-E3) is a mess.

I think I figured out. See picture.

From the key the M or black wire is going to the black wire on the motor. A1 or blue wire from the key is hooked to the gray wire (carb solenoid). A2 is an orange wire from the key and it hooks to the red wire on the motor (alternator).

Does that look correct to you?

What is this black wire coming from the motor near the top? See picture (red circle with question mark). Someone said it was for the lights.

Take the blower housing off and check
IF the stator has a red & a black wire coming from it then yes the red goes to the battery VIA A DIODE OR RECTIFIER and the black was AC feed for the lights usually hard wired into the key switch .
Check the magneto kill wire that comes off the magneto.
It should go to the M terminal on the key switch.
Very important that this wire is either open circuit = running or closed circuit = off.
I would suggest that you make a jumper connected to it or now that you can touch to ground manually to turn the engine off .
If that wire is connected to the battery or alternator for even the briefiest part of a second you will fry the timing chip which requires a replacement magneto.
So hook the mower up, check the mower side of what you think is the kill wire for voltage with the key in every position then do the same with the engine running before you connect it to the magneto .
The wire is AC so needs to be converted to DC before you hook it up to the battery or you will kill the battery .

Attached is the wiring diagram for the motor.

I took off the blower housing as you suggested. The black wire comes from the stator. See picture. The stator has a black wire coming from it and it is not hooked to anything. The red wire from the stator is hooked with a blue connector to orange wire that feeds back to the key at terminal A2. You can see that red wire, blue connector and the orange wire in the picture below.

I no longer have lights on the mower. Can I just cap that black wire with a wire nut that is coming from the stator?

I double checked and I am confident the magento is hooked to the black wired that goes back to the key's terminal M.

Some one has chopped the plug off the end of the alternator wires
The original plug has a diode connected to it that converts the AC ( like your house power ) into DC like your car & mower .
It is shown as a triangle on your wiring diagram
These go bad over time and B & S do not sell them as a service part thus requiring the home owner to buy a new alternator stator .

Now I made the bold assumption that you did not chop up those wires yourself and that is how you got the mower
If you hook the red wire directly to the mower without either a diode or a rectifier then the battery will not charge and it will be destroyed and may even explode due to gas build up .

I bought it that way. What do you suggest I do?

pickenspolitics said:

I took off the blower housing as you suggested. The black wire comes from the stator. See picture. The stator has a black wire coming from it and it is not hooked to anything. The red wire from the stator is hooked with a blue connector to orange wire that feeds back to the key at terminal A2. You can see that red wire, blue connector and the orange wire in the picture below.

I no longer have lights on the mower. Can I just cap that black wire with a wire nut that is coming from the stator?

I double checked and I am confident the magento is hooked to the black wired that goes back to the key's terminal M.

Click to expand...

You do yourself a big disservice as you did understand the previous post
Yes you can cap off the black wire with no problems
Briggs did a really good Guide book that is a free download
No you can not connect the red wire directly to the mower it must have a diode in there
Now you have 2 choices
1) buy a diode & solder it into the red wire
2) buy a rectifier
Your original plug looked like this

The diode is the big black blob near the plug but as the other side of the plug is missing the easiest thing to do would be to buy a rectifier like this



The red wire from the alternator goes to the yellow wire
the red wire from the rectifier goes to the mower orange wire
To work the bolt that goes through the hole in the middle must be grounded so either go into metal or have a ground strap
B & S made a new dip stick tube with a spot to mount it but you can put it anywhere you like with some longer wires

Thank you. I will just cap off the black wire and buy that part.

That is easy enough. Where can I buy a rectifier for that motor?

B & S part number 491546
A stock item for every mower shop & every mower parts retailer
Also all the after market parts suppliers
Cheap item even for genuine B & S
If you do the lazy Ammozone-EvilPay route, make sure it is branded as there are a lot of people selling the ones that B & S rejected because they were faulty .
A local mower repair shop ( the type that sells a lot of used mowers ) will have them in stock and probably a used dip stick tube to mount it on.

Thank you for being so nice to me, patient.

Can I mount it to the blower cover?

I will just have to put a connector on the orange wire to make it work.

You can put it anywhere but there must be a ground wire to the mounting bolt
Remember electricity needs both a + and a - connection

Oh. I thought bolting the rectifer to the engine, which is grounded correct? Is that not enough to ground the rectifer?

If I need to run a wire to the rectifer mounting bolt, doesn't the solenoid have a grounded post? Can I run a wire from that post to the mounting bolt that fastens the rectifer?

I ordered the part. 491546

I am naive I know. Thank you.

The engine is ground
The metal case is also ground so the two of them need to be connected
The blower housing is plastic so if you bolt into it you need to make up a strap from a bolt that goes into the metal part of the engine to the bolt that holds the rectifier in,
Usually you make a wire ( or a pair of them ) to go from the bolt that holds the blower housing on to the rectifier bolt
I usually do 2 one left & one right ( belt & braces approach ) .
Starter mounting bolt is another good place
Avoid using a existing ground wire as a lot of them are actually switched

Thank for all your help. I will get the part next week. I will ground it using a nut I will put on an engine mounting bolt. I will let you know how it works out.

You saved me. Thank you again.

I think I got it right. I mounted the rectifier on the side of the blower cover and ran a black ground wire from the base of the motor (you can see that nut), the the rectifer screw.

I ran the red wire from the alternater to the yellow wire on the rectifer.

I ran the red wire from the rectifer to the orange wire on the motor.

It runs.

Should work.
The test is of course to check the battery voltage engine off then again engine running
Running it should be 13 V or better although it might take a couple of minutes to get there

bertsmobile1 said:

Should work.
The test is of course to check the battery voltage engine off then again engine running
Running it should be 13 V or better although it might take a couple of minutes to get there

Click to expand...

I will run that test. Thank you again for all your help.