K725KH no start

[North Idaho Wolfman]

You wrote this!!!
It has 2 wires that will let it run or not:
Magnetos: Black / White with no connection to run and (-) ground to stop.
Fuel solenoid: Yellow / White for the (+) Positive to run.
Starter solenoid: Trigger is Blue / Red

First 1 There is no black wire running here... It grey
Second The fuel solenoid also does not have a yellow and white. It's red and black. It is also a two-barrel carb. The red is hot and the black wire goes to the ground
Third Start This wire is Violet for the starter trigger.

I'm not sure where you got the colors but does not match what Koler has for their motor IT does not matter what Kubota has in their wiring diagram. They could have different wires to connect to the Kohler cv742-3011 motor but that is a different subject.

Let me add this The oil switch on the sensor also kills the motor with the Kohler wiring diagram and in their wiring diagram. This also kills the spark. I tested that did not spark me at all until I ground that wire now there is a spark This wire is hot and the sensor ground it and it is green.

I add the Kohler wiring diagram page 32-33

Well you know FAR more than all of us, and seem to have it all figured out, so why isn't it fixed and running?

 

[TAFS]

I'd like to see pictures of the actual wiring, especially the engine connector and the ignition switch as well as oil pressure wiring.
The oil switch, even in the Kohler 'suggested' wiring, goes to the oil light then the acc+ on the ign switch, no connection to the magnetos. The oil switch is NC (normally closed). If it was wired to the mag..so....NO spark..until engine starts and makes oil pressure,but can't start as mag is grounded.
You can't go by the Kohler wiring, you have to use the Kubota wiring. Kohler only makes the engine up to their 6 pin connector, after that it's the OEM who decides how to interface to what features the engine may have.

Well, you think that. But I tested that idea I tried starting it with the original oil sensor and my sparkplug gap tester. As I hot wire the motor I never got a spark. I retested and then unplugged it Then ground that green wire and got a spark at .035. ( J ) states that OIl sentry Kill ( green) so the green wire is the only wire that says kill.

The only wire that is not getting a 12-volt power is the carb sensor. we tested the Kubota all three safety systems relays and we have power from them. But yet we cannot start the motor with the switch. However even hot wiring the motor it still will not start that way either. The only other thing that seems not to work is the PTO on the motor it is either on or off with the key is turned or not

I understand wiring and how to test it and read a wiring harness. I have never worked on a zero turn before... So of the people on here that it's a simple wiring. I on the other hand that it's too dam redundant for a lawn mower!! I rather rewire a Polaris GEM 2 Electric golf cart or automotive wiring.

So repeat myself I do want the help but I need some ideas to try Please don't tell me to re-read the wiring harness give me something to look for and test.

We replaced the Timer delay., replaced all 4 relays, the Oil sensor, and the Seat sensor, We replaced the motor rectifier because it was melted. I also replacing one on the magnetos because it not sparking enough. Then we replaced the starter switch due to the key breaking off. The PTO we replaced it because of a continuity test it failed.

 

[TAFS]

Well you know FAR more than all of us, and seem to have it all figured out, so why isn't it fixed and running?

I do not do lawnmowers I do know how to read wiring harnesses. I like the help since I do not work on Kubota of any type. This is not what our shop works on we do a lot of semis, automotive. golf carts and misc stuff. But I try to stay away from lawnmowers, small equipment, and heaving to farming stuff... If you have an idea or something I can test or check I'm up for it. but I'm not up to having someone on just to tell me to reread the wiring harness manual. The thing I HATE IS INTERMITTENT ISSUE. I believe this is what I got myself into...
So I will be blunt If you have a suggestion that I have NOT tried then send it my way!!!

 

[GreensvilleJay]

Easy way to get engine to run

1) disconnect the 6 pin engine harness connector
2) jumper +12 to the fuel solenoid pin on engine side of the connector
3) jumper +12 to starter solenoid coil

you'll spin the engine, have gas and spark

 

[TAFS]

Easy way to get engine to run

1) disconnect the 6 pin engine harness connector
2) jumper +12 to the fuel solenoid pin on engine side of the connector
3) jumper +12 to starter solenoid coil

you'll spin the engine, have gas and spark

Thank You!!! I will try that tomorrow after I replace one of the magnetos.

 

[TAFS]

placingthe new magneto

Easy way to get engine to run

1) disconnect the 6 pin engine harness connector
2) jumper +12 to the fuel solenoid pin on engine side of the connector
3) jumper +12 to starter solenoid coil

you'll spin the engine, have gas and spark

Thank you. After placing the new magneto and unplugging the Kubota wiring harness the motor turned over and it ran great.
So what do you think we need to do to get the Kubota to fire this motor?

 

[GreensvilleJay]

divide and conquor usually wins.
Now you KNOW the engine and it's wiring are GOOD.

next step.

With engine harness disconnected, there's only 3 signals to deal with.
1) +12 to AD solenoid
check the pin for +12 with key 'on'
2) mag kill
check the pin for continuity to ground with key 'off', open when key 'on'
3) oil light
with key on, ground the 'oil switch' pin, light should come on.

 

[jaxs]

placingthe new magneto
Thank you. After placing the new magneto and unplugging the Kubota wiring harness the motor turned over and it ran great.
So what do you think we need to do to get the Kubota to fire this motor?

Know wut? With your understanding of what is required I suggest you re-wire it in a fashion the makes sense rather than straightening out Kubota's Rube Goldberg.

 

[GreensvilleJay]

Probably 99.44% of the wiring is required by law to make it 'kid proof' or at least satisfy some lawyers.

 

[TAFS]

Know wut? With your understanding of what is required I suggest you re-wire it in a fashion the makes sense rather than straightening out Kubota's Rube Goldberg.

I love to do that!! But this is not my equipment I have to ask the customer.... We have found that by keeping the wiring harness in place the key switch is on. Then we ran a hot wire to the signal wire and the motor wire so we could start the motor. Then everything worked the pto switch on and turn the blades. The key would kill when turned to the key off and it kills the motor. this was with the seat switch and the parking switch closed with zip ties

 

[TAFS]

divide and conquor usually wins.
Now you KNOW the engine and it's wiring are GOOD.

next step.

With engine harness disconnected, there's only 3 signals to deal with.
1) +12 to AD solenoid
check the pin for +12 with key 'on'
2) mag kill
check the pin for continuity to ground with key 'off', open when key 'on'
3) oil light
with key on, ground the 'oil switch' pin, light should come on.

This did not do anything... Please read my other post to see how we got it to start

 

[GreensvilleJay]

hmm...40-50 posts ago you said you replaced the ignition switch. Any chance it's the wrong one ?
Always best to ring it out and confirm as 'if made by INDAK they all look alike'.

 

[TAFS]

hmm...40-50 posts ago you said you replaced the ignition switch. Any chance it's the wrong one?
Always best to ring it out and confirm as 'if made by INDAK they all look alike'.

No this was a factory replacement.. We purchased at the Kubota dealer

But this will be an update!!!! We wired the motor and the Kubota wiring back. We zip-tied the brake and seat switch for full-time on. We then tried the key but nothing. So we hot-wired the motor and it came alive. The PTO came on and ran the blades. The wheels turned. Then we tried to move the zip tie off the seat switch with the motor running and the parking brake still zip-tied like the brakes when on, and it died immediately. Turning the key off will kill the motor. but no other safety system failed or triggered the motor to shut off

At this point, we found that we had two issues (1) The whole wiring harness was messed up (2) The brake switch is bad. we tested the for continuity and it worked not sure why it failed

So we order a new wiring harness from Kubota and a parking brake switch.

If this does fix it I'm going to burn this zero turn to ashes!!!!

 

[TAFS]

No this was a factory replacement.. We purchased at the Kubota dealer

But this will be an update!!!! We wired the motor and the Kubota wiring back. We zip-tied the brake and seat switch for full-time on. We then tried the key but nothing. So we hot-wired the motor and it came alive. The PTO came on and ran the blades. The wheels turned. Then we tried to move the zip tie off the seat switch with the motor running and the parking brake still zip-tied like the brakes when on, and it died immediately. Turning the key off will kill the motor. but no other safety system failed or triggered the motor to shut off

At this point, we found that we had two issues (1) The whole wiring harness was messed up (2) The brake switch is bad. we tested the for continuity and it worked not sure why it failed

So we order a new wiring harness from Kubota and a parking brake switch.

If this does fix it I'm going to burn this zero turn to ashes!!!!

Just to update you The mower has left my shop on its power it starts its mows and it's gone. Here is what we replaced the Wiring harness, Starter, Parking brake switch, Seat switch, OIl sensor, (1) Magneto, rectifier, and oil change.

So whatever caused the stock wiring harness to fail it destroyed all these components. So one day I might open up that Kubota wiring harness to see why it caused all the destruction.

S0 Thanks For your Help!!!!

 

[lugbolt]

you want an idea? I have one-and "I" think it's a good one. Follow the dealer. Send it elsewhere. Stick with cars as Z700 mowers are too complex to figure out for auto techs.

I'm not trying to be disrespectful, but I think at this point it might be the best way to alleviate the frustration you're going through. If you own the shop, you know the cost of diagnosing-and remembering that it's a lawn mower, and people don't like to pay $150 per hour, and it takes 5-8 hours to diagnose a real simple system. With that said, how much money have you lost on this already?

Kubota used to pay up to 30 minutes for diagnosis, beyond that the tech is on their own. IF it takes longer, the tech (and shop) is losing money.

I suspect that the dealer wouldn't do it for a reason but I'll keep that suspicion to myself.


lastly, going by the kohler manual can confuse you as Kubota (and other manufacturers that use kohler engines) often have differences in the wiring. So use the Kubota manual NOT the kohler manual. I will admit that Kohler's manuals are written better (so that Americans can understand them) but there's still differences between Kohler manuals and Kubota manuals that will confuse you to no end. Learned this with Kawasaki engine powered machinery back in the 1990's. They're called "SSO" engines, where they're not available to anyone but the dealers of the equipment that they go on, because there are differences between those SSO engines and other engines of the same series. A FC540V on a JD GT262 is different than a FC540V that's on a Kubota....even though they're both FC540V's. Just used as an example.


went through this the very first week I was at the polaris dealer. 2016 Ranger 900, AWD not working. Got power, got ground to the hub coil, so what's the problem? Couple hours diagnosis revealed the ground wire corroded inside the insulation causing a drop between ECU and hub coil. Easy enough fix (repair the harness). Now? Voltage drop test them, find the problem in 10 minutes or less (usually).