[brukru]

I have a 83 JD318 w/Onan B43g that was leaking oil around filter holder, drove it in garage, took off all sheet metal, pressure sprayed everything, dryed elec. components with air, put back together and now NO cranking over, no solenoid click, acts dead.
Here are symptoms:
key on- pto light on when pto switch is in either position.
pto light goes off when unhooked from pto.
12v at trigger (purple) wire at starter solenoid. should be 0v unless key is in start pos.
unhook trigger wire at solenoid and voltage is 0v and jumps to 12v when key is in start pos.

Engine will turn over and start when solenoid is jumped. I thought this meant bad solenoid so popped in a new one, same thing.

All saftey switches are jumped, all fuses are good.

Any ideas where to look next?

 

[Hammerdown-7]

Hello Bruce
There should be a jumper wire at the rear PTO coupler connection if you do not have the rear Optional PTO on your Tractor this Three prong coupler should have a Factoryy Placed jumper wire in it it is close to the other PTO connection simply Trace it back to find it. Some one will be along to Post a wiring diagram for you I do not have one handy. Regards, Kurt

 

[brukru]

Thanks for reply, Kurt.
The jumper wire is in place.
ALSO, the PTO does not engage when I had engine running after jumping the solenoid.
PTO clearance is set @ .018.
I have wiring diagram, but am stumped on where to look.

 

[kencombs]

If there is 12v at the solenoid 'trigger wire', the solenoid should be pulled in and the starter cranking. Something is wrong with that test I think.

Pto light on when switch is either on or off seems to indicate a problem with the TDM. Maybe it got wet inside during the cleaning. Try drying it out really well and report back. Some have reported success with putting them in a very low temp oven.

 

[brukru]

FIXED !!
The solenoid mounts to the side panel. With the panel off, the solenoid was not grounded along with 2 other black wires from harness. I had jumped to ground with a wire and clips on ends. Evidently one of the clips was not making good contact. I hooked up jumper cables from solenoid frame to neg batt, cranked her up and runs like a top!!
Thanks for your replies

 

[hankvc]

Bruce: YES! I did not realize that you had the right side panel off. On the early 318's, with no ground wires in the harness, making sure you've got good ground connections through chassis pieces is important.

As I recall, that starter relay grounds to the side panel through its mounting hardware, and the side panel grounds to the tractor frame through its mounting hardware. That can create problems if you repaint the side panel off the tractor.

A quick test for proper grounding is to connect a voltmeter to the device with one lead and to the battery negative terminal with the other. Energize the device. There should be no more than 1/4 volt drop between the device ground and the battery.

This test also applies on the positive side, with the voltmeter connected between the battery positive terminal and the device energizing terminal. With the device energized, there should be little voltage drop between the two points.

Checking for voltage drops in wiring between end points is the most effective way of finding resistance in the wiring. Typical multimeter ohmmeters may show "a little resistance," if you look carefully, but in 12 volt circuits, 1/4 ohm in a 10 amp circuit will give a 2.5 volt drop in the wiring.

This is an application of Kirchoff's voltage law, basic electricity from the 19th century. "The algebraic sum of the voltage drops in a closed circuit is zero." If the battery is +12 volts, the -12 volt drop should be across the switch, with the device not energized, and across the device when it is energized.

Chassis and engine grounds rely on conduction through their metal, rather than a wire, but voltage drop across them is the same as "in a wire."

Hank