Wiring Issues

[slhilbert]

I recently replaced my clutch and I am in the process of putting everything back together. The wiring is killing me. The dealer copied off the wiring for my MF 135, 3 Cylinder Perkins, Gas.



I followed the diagram to the letter except for two things.
1.) The Fuel Shut Off Solenoid that comes from the Starter Solenoid is not present
2.) My Ammeter gauge appears not to be working so there is wire connecting the two posts together.

The result is that the tractor turns over but the starter will not disengage, it just keeps cranking away until you turn the key off, basically the "Run" position doesn't disengage the starter.

I messed around with it for a while, and decided to wire it per these directions I found in a forum.



The result of this wiring is that the starter starts as it should, but the coil isn't getting any voltage so when you turn it to Run it dies. I went ahead and ran a wire from the positive post of the battery to the coil and the engine continued to run.

I some how managed to wire it yesterday so that it started and ran, but you couldn't turn it off.

I have a 3 post key ignition, could that be the issue or what? Is the fact that the Ammeter gauge is bad an issue?

Thank You,
Stuart

 

[MinnesotaEric]

This post is so that I can look at the image.

 

[MinnesotaEric]

Get out a blank piece of paper and draw in your battery, starter, ignition switch, alternator, voltage regulator, ignition coil, distributor, and fuel shut off solenoid.

Draw the wires that your diagram shows between the components above and ignore everything else.

You just made your own simplified wiring diagram that should be easier to follow.

That said, it sounds like you've jumped somewhere (maybe at the starter or alternator?) your start and run circuits.

 

[Rocky J]

It sounds like you have all three of the wires on the back of the key switch in the wrong place. Are they marked in any way Ex: BAT/IGN/ Sol, if not we need to use a ohm meter and sort that out. Kinda sounds like you are feeding the switch on the wrong spade and of coarse everything after that will be wrong. I agree that first diagram made me feel hopeless. The second one with the pink back ground was great . As far as the fuel shut off lets leave that for last as it will probably just go on the same spade as the coil. That wire across the amp gauge will need to come off, sounds like they were back feeding it to supply power to something that had lost it. Like Eric said you need to make each wire a few separate jobs and not all or nothing like that first diagram.

 

[slhilbert]

Thanks Guys!

My ignition is labeled with B, I, S

It looks like the "B" post is running to the neutral safety switch and then onto one of the side posts of the starter solenoid.

Is the "I" post for when you are cranking the starter and then "S" would be for run, as in the tractor started and now it is running and the starter isn't turning? Or do I have those switched?


Could the jump wire on the Ammeter be my whole issue? Does current usually only flow one way through the Ammeter? Is there a gate? To me that would explain why things aren't working for me. Could I just need a new ammeter and that would solve my problem?


Stuart

 

[Rocky J]

B= Battery , should be hot all the time, comes from the side of the starter solenoid that the cable from the battery + comes to.
I = Ignition, this will go to the coil , the side that is marked + or Batt not the side that says - or Dist
S = Solenoid , this goes through your safety switch to the small tab on the starter solenoid to activate the starter motor.
The amp gauge in theory has some wire wrapped in a coil in it and yes DC current runs one way this build a flux magnetic feild that draws the meter arm one way or the other to show which way the current is running, into the battery or out of the battery, + to charge or - to discharge, this is why that wire cant not be connecting the two leg and be right. If it was charging and one leg was fastened to the gen/alt and the other was connected the the positive of the battery it would indicate current in motion and if you revered the wires it would show it the other direction so knowing which leg is which is important, but it is probably on ther corect and can be checked after you take care of the key switch wires

 

[slhilbert]

Rocky,

Appreciate the info, especially regarding the Ammeter. If I remove the jump wire between the two posts of the Ammeter nothing happens, so I believe the Ammeter is toast. I might just go grab a replacement and call it a day to at least eliminate that as an issue.

Stuart

 

[Rocky J]

If the coiled wire inside the amp meter was burnt off it most likely would not charge the battery, from the first wiring diagram it looks like the wire from the alternator goes through the amp meter on the way to the battery to charge it.That would explain the jumper wire. My Farmal cub is positive ground 6 volt system and so much is backwards it is very hard to focus , that was the tractor that I started talking to my self on, LOL

 

[slhilbert]

Rocky,

I hear ya, I am a programmer with a can do attitude and the ability to read and comprehend, so I am taking a crash course on all of this stuff and I have been talking to myself for a month.

Stuart

 

[slhilbert]

Rocky's post (#6) in the thread did it. I had to switch the two wires at the ignition for B and S. How I didn't switch those at some point during four hours of messing with it last night is beyond, but I did today and for that I am thankful. Thanks Rocky!

Now I am having a carb issue, which I assume to be the last issue I am going to face with this thing. I have created a new post about that. http://www.tractorbynet.com/forums/...c-vintage/371974-carb-issues.html#post4608419

Thanks,
Stuart