Alternator wiring

Airgator

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Kubota M4050
Jan 22, 2022
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I am replacing the alternator on my Kubota M4050.
The old alternator had posts marked 1 &2. The replacement is marked E F & N.
How do they match up? Thanks.
 

GreensvilleJay

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you should post the part numbers of the alternators....
1 &2 sound like GM 10SI series but those would be tabs not posts...
even pictures will help
E could be Earth, F is Field ??
 

North Idaho Wolfman

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Sounds like you got a different alternator than the one that was on it.
Where did you get it from?
And post pictures if you can.
 

Dave_eng

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The wiring diagram, copy attached, shows an M4050 with alternator terminals E,F & N, mated to an external regulator.

If you do not have an external regulator your new alternator is not what you need.

Dave
 

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Mark_BX25D

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I'm thinking that until the OP comes back and gives more information, it's all just shooting in the dark.
 

GeoHorn

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Yep…. as others have pointed out…. someone replaced the OEM alternator with a single-wire internally regulated Delco.

Airgator…now you need to rewire back to the OEM per the wiring schematic for your tractor.
 

GreensvilleJay

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Yes, 'old' alternator is a GM Delco 10SI series , 3 wire ,bodged so white wire of connector goes to the 'idiot' light on the dash.
The 'new' one, the correct one, MUST have an external regulator to work.

You have 2 options...

1) return the new alternator and get a GM 10SI (same as what was there). should be a simple swap,connect then 'up and running'.

2) keep the correct one, hopefully find the original connector on the engine 'somewhere', pray to the Kubota gods the external regulator IS GOOD. If it is, you're lucky.

I suspect either the original alternator and/or regulator 'died' and it was cheaper to bodge the GM alternator in. MY 'gut' says the regulator is pooched..hate to think what that'll cost.

Whatever you decide, be sure to inspect ALL the wiring and connections. BTW the case of the GM unit should have been rotated to 9 or 3 oclock to prevent water from being on the '1' and '2' terminals.
 

Airgator

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Kubota M4050
Jan 22, 2022
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Florida
The wiring diagram, copy attached, shows an M4050 with alternator terminals E,F & N, mated to an external regulator.

If you do not have an external regulator your new alternator is not what you need.

Dave
Thank you, Dave. I appreciate it.
 

Russell King

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I imagine that you can get the correct connector to the back of the alternator from your auto parts store or local alternator repair shop.

If you’re sure that the regulator is stock, the wiring has not been changed dramatically, and the mounting for the alternator will work I would go back to stock.
 

North Idaho Wolfman

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Me personally just take the old alternator and get the same replacement, then you're done!
And that GM alternator is better than the old stock external regulated alternator anyways.
 
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Daren Todd

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Me personally just take the old alternator and get the same replacement, then you're done!
And that GM alternator is better than the old stock external regulated alternator anyways.
May be cheaper to try an armature shop. I'm getting new alternators for $15 more then what it costs to have one rebuilt.

Only one I've run into recently that I considered getting rebuilt was for a Cummins 2.8 diesel. There isn't a new one available period in the world at the moment 😡😡😠😠😠🤬🤬🤬

They found the armature exploded when they tore it down to inspect. Cummins won't even put me on a list to get one when they become available.

Got two ordered from the local armature shop. On back order till the middle of April at the earliest. Been waiting two months already. 🙄🙄🙄