Kubota ZG127 issue that I could use your help sorting

[Hampshire]

Hi everyone,
I suspect some sensor issue. I cant get the mower to start. Battery is charged. I can however jump the starter solenoid and engine starts right up. While in Neutral, PTO off, and brake on. I can hop off the seat, still runs. If I sit down and try and take off the brake, it stops. Same if I pull the handles out of neutral. Some sort of sensor malfunctioning maybe?
Thoughts on what I do next?
Much appreciated.
Shawn

 

[Dave_eng]

Edit your first post and remove your email.
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I have a notice in my archives dealing with a brake switch recall on gas powered ZG series.
Look at the cover of the WSM I have to see if it covers your machine .

The "truth table" shows the engine will only start under one special set of circumstances. The key one someone on the seat.

If you think the WSM will cover your machine just post that fact and I will contact you by private message

Dave

 

[Mark_BX25D]

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[Hampshire]

Ty for the help and heads up. Edited my OP

So its likely the issue is faulty seat sensor?

 

[lugbolt]

probably brake switch. It is THE most common failure point on the ZG100 series mowers.

The brake switch is a NO/NC switch-4 wires. Two different switches built into one. One set of contacts opens (is normally closed) when you move lever, the other set of contacts is normally open, and moving the lever closes that side of it.

If one side or the other fails, and it's really common, it won't crank over but often people will bypass everything using a wrench or screwdriver. all that does is tell ya if the battery has enough juice to crank the engine, and if the ground is sufficient to crank over; it doesn't telly you a single other thing about the system.

 

[mikester]

probably brake switch. It is THE most common failure point on the ZG100 series mowers.

The brake switch is a NO/NC switch-4 wires. Two different switches built into one. One set of contacts opens (is normally closed) when you move lever, the other set of contacts is normally open, and moving the lever closes that side of it.

If one side or the other fails, and it's really common, it won't crank over but often people will bypass everything using a wrench or screwdriver. all that does is tell ya if the battery has enough juice to crank the engine, and if the ground is sufficient to crank over; it doesn't telly you a single other thing about the system.

Brake switches usually fail open meaning your engine will get cut if you get off the seat. Mine gradually failed and I replaced it last summer. Engine would cut out when I stopped to get off the machine with the engine idling.

I would suspect the seat switch. If it fails open its no go trying to move the machine. You don't need a seat sensor in park mode.

 

[lugbolt]

Brake switches usually fail open meaning your engine will get cut if you get off the seat. Mine gradually failed and I replaced it last summer. Engine would cut out when I stopped to get off the machine with the engine idling.

I would suspect the seat switch. If it fails open its no go trying to move the machine. You don't need a seat sensor in park mode.

ain't seen a seat switch die one one of these yet. But hundreds of brake switches. Not saying seat switches don't fail, just saying that out of thousands of them I've worked on, I have yet to have to replace a seat switch.

OP-get your service manual out and diagnose it per the book. May not be the answer you wanted to hear but at least you'll learn how the systems work together.

oh and by the way if you have to replace the brake switch, and you don't have a way to lift the mower up high (like 4 foot high), you may find it easier to remove the LR wheel. The switch clips into the crossmember; the clip is part of the switch. Leave the wire plugged in and then grab a good sharp cold chisel, and break the plastic clip off of the bottom of the switch. Then remove the switch, and unplug the harness connector after you lift the switch out of the crossmember. Installation is the exact opposite except you don't have to use a chisel to install it