1872 starter and pto problem

[FrankF3]

Sorry for the long-winded post.

Ok... going back to basics, sounds like you could have several problems. A charging problem and a wiring or interlock/key switch problem that prevents starting. Let's just work on the starting problem here. Check the fuse on the front of the dash below the steering wheel and make sure it is good. If it is good, put it back in, then raise the hood. Now, turn the key to the first position (running with lights on) The lights should come on. If not, check with a meter to see you have 12V on the connections on the back of the Ammeter. If good there, you should have 12V on the back of the keyswitch on the black wire feeding the keyswitch. If not trace out where you are dropping it. On the back of the keyswitch, you should also have 12V on the white wire (alternator) and the blue wire (lights). If not, you may have it miswired or a wrong or bad switch.
Now if the lights come on on the first position, have a helper turn the key to the start or turning over position (just like in a car). If it does not turn over, check the back of the key switch for 12V on the red wire, this winds up telling it to turn over. If no 12V here, bad or wrong or miswired key switch. If you have 12V here, next make sure the PTO switch is in the off position. Try starting again. Still not turning over, check the back of the PTO switch, for 12V on BOTH red wires (terminals C and D - WHILE TRYING TO TURN OVER VIA THE KEY SWITCH) If you have 12V on terminal C but nothing on Terminal D with the switch in the off position, you probably have a bad PTO switch. (This caused a no start recently on my 1772) If you have 12V on both terminals ( C & D - red wires on the PTO switch) check the brake switch next.

Remove the tunnel cover and check the brake switch, (my father's 1872 failed to start because of a broken paddle that presses the brake switch).

Above all be very careful not to get caught or wound up in any rotating or moving parts while troubleshooting this problem.

Starting at the other end of the problem, If you lift the seat and quickly jump 12 to the SMALLEST singly attached wire on the start solenoid that is located along side the battery, this will tell you the solenoid is good and the problem is probably in one of the switches mentioned above.

Good Luck.

[pexprmnt627]

Thank you so very much for the detailed troubleshooting plan!! I will let you know what I find out. Thanks again!