Safety switches on my zero turn

[Larry]

My Kubota zero turn has been having intermittent trouble with the engine dying when I get off to open a gate or something. Wiggle the brake lever and the safety switch makes contact. Acts good for a while. Last week it wouldn't start but I was able to get going by shorting the posts on the start relay.

Rainy day today, so I decided to tear into it. It has five safety switches, two additional relays, a start switch, the solenoid, fuses, and a couple of diodes in the starting circuit. All located in places impossible for human hands to reach. I'm fairly good at reading electrical schematics but Kubota makes this a challenge also. None of the wires have the color on the schematic. At the end of the day I'm no closer to a fix than at the beginning.

My thoughts have turned really dark and I have a great way to put the Kubota out of its misery.

Boats have a simple kill switch which is normally reliable but easy to diagnose/fix, why not on a mower?

Ok, anybody have recommendations for a new, simple and reliable zero turn?

[Southside]

Jersey cow with a bull calf at her side.  No safety switches to worry about and the calf will be better eating than the Kubota. 

[Magicman]

I do not know which is better, but I absolutely know your Kubota frustration.  I have replaced that brake switch and I can't say here on the FF what I thought.  I did squish some grease into the connection to try to prevent future moisture intrusion.  So far, so good.

[Raider Bill]

I bet they all are like that now.
My Ariens is about 20+ and has 3.

[Don P]

We decided spilling hot coffee in your lap was someone else's fault. We point and talk about Indian workers in sandals welding by squint. When he steps out back to pee there's tigers in the bushes. It's all about perspective. I thought the PTO switch was a good idea to leave.

I was deep on the Honda replacing a crank position sensor, having removed a good bit of the accessories, a crank pulley, valve cover, and timing cover. It could pick up off the pulley and be a 5 minute job if someone cared. All the while thinking, it has a distributor... when did we forget those parts are timed with one another?

[YellowHammer]

Intermittent dying indicates a bad switch, most likely not a diode or relay.

I had mice get into mine, and I ended up bypassing pretty much every one.  This way I didn't have to get to the switch, just the wires coming from the switch somewhere.  I found a few with a warbler, but either way, I cut them, put spade lugs on either end and connected them together. 

I'm not sure if there is anything better than the Kubota, we bought the Pro model and finally sold it after 18 years, and have since bought their new pro model and it is even better.

[Magicman]

I wish that I had a schematic, but if I had it I would probably wish that I didn't.  I tried bypassing but there are issues.  The brake has to be energized to crank, but it has to be off to go, so there is more there than just a switch.

That electrically energized PTO is sorta the same on my Kubota tractor. 

[WV Sawmiller]

Don,

  That's why instead of peeing in the bushes this highly trained technician pees in the corner of the building where he's working instead of going outside. Been there - done that when working overseas with what we used to call TCNs (Third Country National). The terms have changed but not the quality.

[Larry]

Three out of the five safety switches have two sets of contacts. One is normally open while the other is normally closed. This adds a whole new level of complexity, cost, and unreliability. A simple switch bypass becomes problematic. One solution I suppose is to bypass the whole mess, except for the pto switch.

[doc henderson]

I have a walker with a 25 hp fuel injected gas engine.  It is repairable.  It is very expensive up front.  I do not know your age, but it will prob. be left to someone in your will.  It takes two blades, and they are 14 bucks each, so consumables are not bad compared to up front price.  I have the bagger that dumps.  they are commercial so you can get one that elevates, and dumps like into a truck or trailer.  They also have diesel, but even more money.  the nearest dealer for me is in Wichita, and i have taken it once.  They delivered it.

[Magicman]

A simple switch bypass becomes problematic. One solution I suppose is to bypass the whole mess, except for the pto switch.

Yup, which is why I would like to have a schematic. 

[Magicman]

I just replaced my starter, and the diagnosis was a bit iffy not knowing whether all of the safety switched were doing their jobs.  I found a replacement for ~$50 & free shipping from an ebay seller.  It was a like for like bolt on and it fixed the starting problem. 

[rusticretreater]

I have a Kubota BX-25 tractor and have dealt with these things several times.  Electrical gremlins confound most people, but there are a few things you can try to get things moving again.

One of the issues is low voltage/amperage.  The manufacturers use the thinnest wire they can get away with due to costs.  This can result in low current when things get older and every connection suffers a bit of corrosion. When you see those wires that have a bit of corrosion, but it doesn't look all that bad.  Think again.  Many is the time I have clipped off an old connector, exposed clean wires and made a new connection.

Check the current at the plugs for switches.  If should be at 12v+.  If not, start cleaning things up.  Buy a can of electrical component cleaner and spray it into the plugs then slide them on and off the switch lugs to cut through the corrosion.  It never hurts to clean the ground connections.  I also use dialectic grease on components to prevent corrosion.

Once I had a switch that appeared defective, but when I removed it I found the plastic that holds it secure in its slot had cracked on one side and it was sagging a bit.  Bypassing switches sometimes has its benefits, but the seat rollover safety switch should always remain.

@Magicman One thing that happens is that there is not enough amperage available on the wire that activates the solenoid.  The famous "click" but no start condition. There is a popular kit that has a relay that switches battery current directly to the solenoid instead of using current through the wiring harness.

[barbender]

Don, I think I posted before about that jury awarding a paralyzed kid millions from Kubota, because he was riding on an attachment on a Kubota skid and the operator raised the loader and crushed him.

Another family was just awarded a multi-million dollar settlement from CRC, who make aerosol cleaners etc. Someone was driving down the road huffing a CRC product, passed out iirc, and hit this woman's car head on killing her.

These settlements were awarded by juries of our peers. You can thank them and attorneys for all of those switches.

[barbender]

 Rustic, a common failure on Case 1845c skid loaders is the wire to the key switch is insufficient size, so it tends to not supply enough voltage to the starter solenoid. I finally did the popular but somewhat hokey (imo) modification of a smaller solenoid, to run the solenoid. It was much simpler than running all new wiring🤷