Wiring diagram for lawn tractor

I wonder if any of the dopers ever had to work on the wiring of a Jacobsen riding mower with a Kubota desiel engine. I looked on line for my husband and found no help. It could be that the tractor is old so they don’t carry it anymore. He has checked out the Switch, the Solenoid , the starter etc. and feels it is somewhere in the wiring.

Thanks ahead of time.

If it is an old model it should be pretty straight forward and easy to check. Did your husband check for voltage at these various points? Bad grounds are very common. Some folks get confused on how to check a solenoid if they are not familar with them. They have tow small poles and two large poles. One of the small poles is energised by the key and the other small pole should be grounded. The hot flows through from one large pole to the other and to the starter. He needs to check both the control wire and the ground wire as well.

This strikes me as an odd way to put it, as in the course of checking those components one would normally be checking whether or not the wiring was okay. In other words, if proper testing was done, there should be no question as to whether or not there’s a wiring problem.

I assume the problem is that the starter will not crank. (If that is not the problem, provide us with the symptom(s) observed and we’ll go from there.)

In my experience (automotive), most solenoids have one small pole (the “trigger”) and the winding is grounded through the solenoid housing to the body/frame (remotely mounted solenoid) or through the starter housing (starter mounted solenoid). If there’s a second small pole, it provides power to an additonal circuit during cranking. Maybe it’s different on lawn tractors.

Basic testing can be done with a test light. A good place to start is at the solenoid.
>The battery cable pole at the solenoid should show power all the time, and its connections at both the battery and the solenoid should be clean and tight. If not, repair or replace the battery cable.

Now go to the trigger terminal on the solenoid.
>It should show power when the ignition/starter switch is turned to the “start” position. If it does, that indicates the components and wiring up to that point are okay. If it doesn’t, continue testing at the ignition/starter switch.
>If it’s a remotely mounted solenoid and has power, but doesn’t click and connect the battery cable pole to the starter cable pole, the solenoid is faulty. (If it has a separate small ground pole as described by HoneyBadgerDC, ground that directly with a jumper wire and retest – no click = bad solenoid, clicks = bad ground wire which should be repaired or replaced.) ETA: If it’s grounded through the housing, make sure the mounting makes a clean tight connection to the body/frame.
>If it’s a starter mounted solenoid and has power, bypass the solenoid by using a good-sized screwdriver to directly connect the two large solenoid poles together. Starter cranks now = solenoid not working, no crank = bad starter. Solenoid not working can be due to faulty solenoid or faulty starter – this is not a problem with automotive starters as the starter and solenoid are only available together as a unit.

If there is no power to the solenoid trigger during “start”, the next thing to check is the ignition/starter switch.
>One terminal at the switch should have power all the time. If it doesn’t, test the wiring between the battery and the switch.
>If it has battery power per above, and it’s a combo ignition/starter switch, one terminal should have power when turned to the “on” position, and another should have power when turned to the “start” position (a starter-only switch won’t have an “ignition/on” function). If not, the switch is faulty. If it has power at “start” but there’s no power to the solenoid trigger, test the wiring between the switch and the solenoid. If it’s a combo switch and has more than three terminals (battery, ignition, start), the function of the additional terminals should be determined before judging the switch.

Also, don’t discount the fact that there may be various interlocks that could stop current from reaching the starter motor, things like a seat switch or a deck up position switch.

Good point. The essence is that each component in the circuit should have power in and power out. A wiring diagram or someone familiar with the model would be most helpful if it has more components than I figured.

Thank you so much for your information. I will pass it on to my husband.

Thank you, I will pass it on to my husband.

I will pass on the information. Thank you

As Gary said above, if the solenoid only has one small pole the ground is built into the body of the solenoid and how it mounts. The solenoid still has to be checked for ground.

Kubota lawn tractors are notorious for their damn “safety” interlocks. Our Kubota takes anywhere from one to thirty minutes to start. My routine involves jumping up/down on the seat, setting/releasing brake, jiggling throttle, raising/lowering mower deck, etc. It always eventually starts.

Some of the answers I got from other dopers helped a little, he said the starter now works but doesn’t stop running when it should. He now is checking the wiring again, he bought the Mower from our son-in-law but our son in-law had hired a man to cut the lawn for his business and didn’t know the problems, Our son in-law said they used to Jump start the tractor.

I will mention to my husband about the seat usage. That may help a lot, because when he got of the tractor the first time he tried to use it, he had to get off and then the mower wouldn’t start!

if this is your first riding mower then finding out about them in general from an experienced person would be good for your safety and life of the machine.

as mentioned there are all kinds of safety interlocks that you may have one or more of.

We have other mowers, but this one is a lot bigger and we have 5 acres to mow.

My husband bought it to help out our son in-law. He never had a problem fixing any of the other mowers. and this one mulches the grass, so we do not need to rake when the grass is taller than we like, because we don’t like the grass to turn brown after it is cut. Should it rain it is harder to rake and haul.

I am grateful for the dopers help, and thank you.