1976 B100 Wiring Diagram?

[stevew 0]

I am having trouble rewiring my 1976 B100, 10hp K241S. My replacement starter solenoid (and the original starter solenoid) has 4 connection posts total, 2 large and 2 small, none of the posts are specifically identified in any way- I do not know the wire placements for this part. I know that the pos+ battery terminal connects to one (large) post and that the other (large) post connects to the starter. I do not know what connections are made to the smaller 2 posts and whether the connections are "side specific". I believe that the smaller posts connect to the key switch tab "S" and to the ammeter, but am unsure if they are side specific on the solenoid and (+) or (-) on the ammeter. Many of the pictures and diagrams I've found depict only 3 post solenoids? Would appreciate any directions from a B100 owner with a working charging system.

Edited July 23, 2014 by stevew

[KC9KAS 4,741]

  Did you look in the manuals files here on Red Square?

[rmaynard 15,431]

The correct solenoid for the B-100 is a three terminal, with the small one being connected to the start circuit. The body of the solenoid is grounded.

[rmaynard 15,431]

Here is the wiring diagram for your B-100.

 

 

 

With a two terminal solenoid, one of the two small post is 12 volts, the other is usually ground. If they are not marked, you will need a multimeter to determine which is which.. Some two terminal solenoids are also internally grounded, meaning that one of the two small posts connected to the metal case of the solenoid.

[gwest_ca-(File Mod) 11,037]

Bob explained the original 1 small terminal solenoid design.

 

There are 2 different versions of the 2 small terminal solenoids.

 

Try the single wire from the switch to each terminal with the solenoid mounted and see if it works.

If not add a ground wire to the solenoid mounting bolts to make sure the solenoid body has a good ground. If it works now you are done leaving one small terminal unused. (This 2nd terminal bypassed the ignition resistor for hotter spark in some automotive applications)

 

If it doesn't work ground the 2nd small terminal - dosen't matter which wire goes to which terminal. This design has a metal body that is isolated from the magnetic coil for applications where the solenoid is not mounted on a metal chassis. The 2nd small terminal is provided for convenience.

 

The ammeter feeds the ignition switch and from there the S terminal feeds the solenoid through the clutch switch.

 

Garry

[stevew 0]

In the wiring diagram, one ammeter terminal goes to B on the key switch (light green), the other ammeter terminal appears to go to the solenoid at the positive battery lead connection (large post, black).

If I understand correctly, ONE of the smaller switching terminals on the solenoid will route to S on the key switch, leaving an empty solenoid terminal that may be merely a ground.

Question.  Which ammeter terminal (+ or -) goes to solenoid? The ammeter terminals are marked for positive and negative.

Thank you for the diagram.

[rmaynard 15,431]

The plus terminal on the ammeter is connected to the battery terminal of the solenoid. All power for the tractor goes through the ammeter with the exception of the high amperage connections to the starter.

[stevew 0]

Thank you for the help. I followed the diagram as best I could, but I'm still having no luck - afraid I'm at a loss. I'll have to see the mechanic and hopefully learn what I'm doing wrong.

Tough to give in, but probably safer. Thanks again for the help.

[rmaynard 15,431]

PM sent.

[Save Old Iron 1,566]

In the spirit of a picture is worth a thousand words ... this may help