B21 no start mystery

[Marcipaw]

SOLVED. I just got this machine, it was used by septic tank company, thats all I know. Clutch, seat kill sensors are disabled
I shut it off after about two hours of snow removal during blizzard. I came back next day and when I turn the key all of the usual light came on but when tried to start it all power disappeared, power came back after a minute or so, but when starting it just clicked and power was gone again. Poped the hood open and noticed that red wires going to alternator and starter had insulation melted on them. After ripping the wire harness apart I have found they were shorting with oil pressure sensor wire, so that is fixed, but still no start. I have 12.5v on starter and battery connections are cleaned
Right now there is no power when turning key, all fusees are good and I dont know what to do next...

 

[Bulldog]

Not sure if yours has them but some tractors have slow blow fuses between the battery and the starter.

 

[85Hokie]

Check that slow blown inline fuse as BULLDOG pointed out - the shorting of those two wires will create havoc as you try to locate the problem.

Have you tried 12v straight TO the starter with a jumper cable? You can then determine IF the start is toast. All that heat can cause a lot of weird stuff to happen, you must rule out one part of the equation at a time.

 

[coachgeo]

Sounds like a ground to me.

 

[Marcipaw]

There is no slow blow fuse, new wire goes directly to starter. Wiring was not taken care of by previous owner

 

[Dave_eng]

Likely blown fusible link.
It may look like this picture.
The fusible link is the loop of wire designed to burn out like a fuse while the insulation remains in place.
Dont replace it with ordinary wire or the next time you will have a fire.

The fusible link may be near the starter solenoid or like this photo at the fuse box.

Suggest you google fusible link to learn more about them.
Dave M7040

 

[North Idaho Wolfman]

Most likely the cause of the melted wire insulation is a bad battery cable/ or connection, can be either negative or Positive side, it causes the resistance on all wires to go up and create heat.

 

[Marcipaw]

Right on Wolfman. So it is solved, it was bad ground wire connection going from frame to battery, it was painted over. Once I removed the bolt it was nothing but oxidation, that lack of ground made positive wired nice and hot.

 

[North Idaho Wolfman]

Yea it wouldn't seem possible for it to do that, but it does and it's almost never pretty.
Glad you got it figured out.