Z125S starting issues

[Flying Biker]

I did a search and came up empty handed so I figured I would start a new thread for my no start Z125S zero turn. It was that time of year to bring it out of hibernation and I did my normal preflight checks and everything looked and spec'ed out good. Went to turn the key and nothing but clicks from the solenoid. Okay, lets take another good look at the battery and see what voltage it has and it looked good. I even put a jump pack on it "just in case" and still nothing. I checked "status" of each safety switches starting with the seat. While exercising each switch one by one, I would turn the key to see if there was a change in "clicking" and I got what I was expecting. I could definately tell that the switches were having an effect on the safety system. I even checked not only the 5 am "starter" fuse, but I decided to ohm out all fuses including the 30 amp main fuse. I then went ahead and jumped the solenoid and she roared to life. I ran her for about 30 minutes doing a quick mow job and brought her back to her paddock. I shut her down and again attempted to restart her. Nothing but clicks. I looked on the internet and my kubota app for a wiring diagram but that system seems to be kept in a locked vault somewhere. I need to see if I missed anything and or to see what kind of voltage/amps I would expect to see on the poles of the switches to make sure I don't have something with a little more resistance than it should or some other electron anomally. At one point during my quest of trying to spec things out, I came across 2 relays that were tucked up under the seat and hidden. I am trying to figure out what I am missing? I did switch out the solenoid for a brand new one and last year I changed out the brake safety switch, and maybe 2 years ago I had to change out the ignition switch.

Any words from the brain trust on what I need to look at/for?

 

[Russell King]

Since the starter and solenoid and battery all seem fine I would suggest that you could just ad a relay that gets “fired off” by the existing wiring through the safety switches. As you do, I suspect that one or more of the safety switches is dropping too much voltage to reliably fire the solenoid off.

See this diagram

Of course you can try to search out and repair or replace the safety switches but this would get you going in the meantime. The wire to the solenoid may be coming from some relay or computer already that won’t fire the solenoid until every separate safety switch reports the correct signal. Without the wiring diagram you just don’t know until you trace out the wires.

 

[Flying Biker]

Since the starter and solenoid and battery all seem fine I would suggest that you could just ad a relay that gets “fired off” by the existing wiring through the safety switches. As you do, I suspect that one or more of the safety switches is dropping too much voltage to reliably fire the solenoid off.

See this diagram
View attachment 173288

First off, thanks for the quick reply. This is very doable and I have a few relays already on hand. But my solenoid actually has 2 spade terminals on it. I will have to wait till tomorrow to trace where these two separate wires go so that I would know which spade terminal I would need to take post 30 to. I am assuming I could disconnect the key switch wire that goes to the solenoid, place it on post 85, then route Post 30 to that same post (assuming that the other spade post is the ground). Does that seem right?

 

[Russell King]

That two wires on one solenoid that you describe is a new one to me. It may have to do with safety or theft prevention. Or is it like an older Ford solenoid that has two small wires and two large wires?

I can only say that most times you take the one wire off the solenoid and put it on terminal 85. Then the wire from terminal 30 replaces the wire on the single wire solenoid.

 

[Flying Biker]

This is the way the solenoid is on this mower. the wire on the left side is solid blue and the wire on the right is blue/red. I believe the solid blue is coming from the ignition???

 

[JasonW]

My ZG127 was the same way. One is ground and the other is switched power(key on cranking position). How did you originally “jump” solenoid in the beginning?

 

[Flying Biker]

My ZG127 was the same way. One is ground and the other is switched power(key on cranking position). How did you originally “jump” solenoid in the beginning?

Key on, positive post to starter side post. You can actually see the arc marks on the starter side post.

 

[Russell King]

Okay that is like an old Ford vehicle (may still be that way, I don’t drive Fords any more).

So here is some more trouble shooting steps:
Don’t remove both wires at one time so yo don’t get them mixed up!
Remove one of the blue wires and connect it to a volt meter positive lead. Ground the negative lead to the frame or some bolt that is grounded. Operate the key switch to crank (you have to be like you are trying to start the engine- sitting in seat, …safety switches happy. You should get 12 volts on one of those two blue leads. Make a note of which wire it is or if neither blue wire shows any voltage.

Once you are sure blue wire is supplying voltage to the solenoid then you can bypass all safety switches by supplying 12 volts directly from the battery to the solenoid terminal that normally receives 12 volts. The starter should crank engine. DO NOT touch the large battery cable size wires or terminals when you do this are it may get exciting! I would attach a wire to the solenoid terminal and then touch the positive battery post (clean the top of the post).

If you wanted to install the relay per the previous discussion that wire (battery to solenoid) would be cut and connected to 87 and 30 terminal. The blue wire you identified as the fire wire would connect to terminal 85. Terminal 86 needs to be grounded.

But that won’t fix it if the starter did NOT crank in the above test.

If you get no voltage readings on either of the blue wires there is a problem somewhere between the battery and the solenoid like a safety switches which covers a range of electrical problems!

You may need to learn about voltage drop testing to help on that but let’s see what happens above.

 

[whitetiger]

Here are the secret wiring diagrams.

 

[JasonW]

Did I miss it somewhere? The solenoid is clicking but not starting the engine? But you jump the solenoid and it starts?

Have you verified the solenoid is functioning properly? My ZG127 seemed to go though one a year.

 

[Flying Biker]

Did I miss it somewhere? The solenoid is clicking but not starting the engine? But you jump the solenoid and it starts?

Have you verified the solenoid is functioning properly? My ZG127 seemed to go though one a year.

Other than just buying a new one and getting the same result as I got from the one I took off, no, I guess I didn't check to see if it came defective out of the box. I will double check that, but I have faith it is working as advertised.

 

[Flying Biker]

Here are the secret wiring diagrams.

You are Awesome.

 

[JasonW]

Other than just buying a new one and getting the same result as I got from the one I took off, no, I guess I didn't check to see if it came defective out of the box. I will double check that, but I have faith it is working as advertised.

I miss read your first post it seemed you replaced it last year. The post is hard to follow.
All the prior testing didn’t lead to testing the original solenoid?

Your post reads that the starter solenoid is clicking when you have the key to the crank position? But nothing is happening? As in it’s not making contact inside the solenoid.

 

[Flying Biker]

Okay that is like an old Ford vehicle (may still be that way, I don’t drive Fords any more).

So here is some more trouble shooting steps:
Don’t remove both wires at one time so yo don’t get them mixed up!
Remove one of the blue wires and connect it to a volt meter positive lead. Ground the negative lead to the frame or some bolt that is grounded. Operate the key switch to crank (you have to be like you are trying to start the engine- sitting in seat, …safety switches happy. You should get 12 volts on one of those two blue leads. Make a note of which wire it is or if neither blue wire shows any voltage.

Well the test failed and it didn't even register even a blip on the meter on either the Blue or the Blue/Red wire.

I pulled apart a bit of the the wiring loom that goes to the seat safety switch, which according to the above chart is the only thing between the key switch and the solenoid other than that diode. Unfortunately we had dinner plans tonight so I had very little time to dive into that circuit more, but there is always tomorrow. I am starting to become concerned that I have a diode issue. I will check to see if I am getting 12v at the 5amp fuse and follow it to the key switch to make sure the switch is getting that 12v through to the 30amp fuse from the battery.

 

[Flying Biker]

If you get no voltage readings on either of the blue wires there is a problem somewhere between the battery and the solenoid like a safety switches which covers a range of electrical problems!

You may need to learn about voltage drop testing to help on that but let’s see what happens above.

I couldn't let it rest tonight and went back out after dinner. I do have 12v at the 5amp "start" fuse but I got a bit of a different symptom tonight during the testing. I am now getting a soft buzzing sound from one of the relays I spoke about earlier. In looking at the diagram and tracing the seat switch wires, I believe it is the #9 starter relay. I have a yellow wire that I believe is coming from the seat switch that goes into that relay and a blue/red wire also on that relay which I believe is the blue/red that goes to the solenoid. I did check voltage again at one the blue/red wire at the solenoid and it is still showing no voltage. So I either have a bad #9 relay, a broken wire or the diode is bad. I couldn't get to the relay tonight to see if it was getting any voltage at the blue/red wire but that will be my first order of business tomorrow.

 

[Russell King]

I do recall reading posts about relay failures causing problems AND I think it was starting problems. I recall that there were at least two identical relays mounted close to each other so they could use one relay to replace the other for testing.

Did you test the solenoid? I guess you really don’t know which wire provides power since the wiring diagram doesn’t show wire colors (that I can figure out).