We have a 1992 bobcat 743B loader. It ran just fine then one day stoped when I turned the lights on. Later after disconecting the lights I was able to start the vehicle by first jumping the starter key until I heard the fuel solenoid click. Then turning the key to start it would start and run. Once again if I turned the lights on the engine would die. ran it that way for a few days. Now no click even with the lights disconected and the engine will not turn over with the key at start. Checked connections to starter and battery all seem good. Jumped the positive solenoid side to the start wire and turned over the engine but would not start. Then while jumping the starter - held the fuel solenoid to the open position and was able to start the engine. closing the solenoid by hand stops it. replaced the fuel solenoid - turn the key and nothing unless I jump the starter and hold the solenoid open. HELP any ideas what is wrong ??
Key switch is my first guess. But get a long piece of wire and use it as a test lead for your multimeter to see what's not getting power when it should, and work your way back. Do you have a wiring diagram? mighty helpful. Or start at the key switch with the multimeter and see that it's getting power first, keeping power with a load (weak connection feeding the switch?) and then sending power at the right terminals. Or somebody will come along and say "wiggle this connecter underneath there and that will do it".