Mahindra 3616 won't start

[Don the fitter]

My tractor will only start if I jump the starter directly from the battery. I think it might be the starter relay but not sure where it is located. Not very good at this stuff but just need a little advice. Thanks in advance

 

[RjCorazza]

Not familiar with your particular machine, but the best place to start is to remove / clean / tighten all cables and wires in the start and cranking circuit... Including the main ground to the frame. Also load test the battery.
If you hear a momentary "click" when trying to start the tractor, the problem is very likely a high resistance connection somewhere.