Well i changed the title to be more descriptive and invested in a brake switch which did not solve the problem.

I would still suspect that seat switch. Some of 'em can't be jumpered.

As rcbe states, I agree. Everything about your symptoms shouts "SEAT SWITCH". The logic behind this is because: Engine runs when brake pedal is locked and/or PTO switch is OFF. The interlock circuits will permit running of the engine when the seat is unoccupied ONLY WHEN THE BRAKE IS LOCKED and the PTO switch is OFF.
So you are sitting on the machine and you let up on the brake pedal.........the seat switch circuit believes that the seat is not occupied, and that is not permitted, so it kills the engine. Same thing when you engage the PTO switch......the seat switch circuit thinks the seat is not occupied, so it kills the engine. Post the serial # of your STX 38 so we might try to view an online wiring diagram of the machine. I'm am not saying the switch itself is defective (though it could be). I am saying that the circuits that comprise the Operator Presence Sensing system have some kind of fault. Deere and other OEMs sometimes add an Operator Presence Sensing relay to the electrical system. The problem could be corrosion or a broken wire somewhere, but it still comes down to "The system thinks the seat is empty."

Makes sense to me, none available in my area so I'll have to wait and see i guess.
Funny thing is when i took off the relay asm it ran with the brake off but not the pto deck on.
I have a wiring diagram in my manual which i can't make heads or tails of, that i will post if i can

Page 17 for the schematic click the url
Mownie, you must have confused posts and I'm glad you did.
Is there a way to check seat switch and power coming to the switch?
Thanks to everyone for your help.
Joe

Here is a link that might be useful: Ranch king pro manual

Joe,

Looking at the schematic all I can see the OPS relay only cuts off the PTO solenoid and not the ignition! Any chance the wires to the PTO are rubbing on the frame someplace and shorting things out?

Everything looks good, wires still look new.
The relay then is probably good ?

***"Mownie, you must have confused posts and I'm glad you did."***
Absolutely right I got my note sheets mixed up.
OK, I'm in focus on the RK diagram and I noticed a technical error in the diagram. See the image below and find the RED X I have drawn into the "corrected diagram".
In the Ranch King diagram it appears that the green wire from the seat switch "intersects and joins" the black wire (magneto kill wire circuit). Of course, that can't be and is actually just an error of the drawing. My corrected image shows the true nature of the circuit.
But the OPS relay is configured to Kill the engine via the PTO switch or the clutch switch when the seat is unoccupied.
Refer to the diagram: Any/all wires that are common or continuous with the ign key switch "M Terminal" will ground the magneto and kill the engine WHEN connected to GROUND by any means, whether it be through the action of the OPS relay or a short to ground because of a defective wire somewhere in the machine wiring.
In this diagram, all wiring common to the "M Terminal" converge to connect to the # 87A terminal of the OPS relay.
Whenever the OPS relay is "de-energized", 87A is connected to the # 30 terminal of relay which is connected directly to the chassis ground. In order for the "Magneto kill" circuit to be deprived of its ground (which will permit the engine to run), the # 85 terminal of the relay must be provided with 12V from the seat switch (assuming the relay is good) to ENERGIZE the relay causing the the relay contact to move away from 87A terminal and make contact with the 87 terminal of the relay. This "switching of contact" will then provide a GROUND for the PTO clutch to enable the clutch to engage, while at the same time REMOVING THE GROUND from the magneto kill circuit and permitting the engine to run.
Do not be confused here............the OPS relay will kill the engine via the clutch switch and PTO switch.
Here's what you need to check with a test light or volt meter.
Key switch in the RUN position.
With the seat switch active (someone sitting in the seat) you should be able to detect voltage at terminal # 85 of the relay plug (have a sketch of the relay to look at while you test). If you do not detect voltage at terminal # 85, go to the seat switch itself and check for voltage. With the seat switch activated you should detect voltage on both wires. When deactivated you should have voltage on just one wire.
If you detect no voltage at all on the seat switch, there is a fault in the wiring leading TO the seat switch.
If you detect voltage on just one wire at the seat switch regardless of the position the switch is in (activated or de-activated) replace the seat switch.
If you DO HAVE VOLTAGE at relay terminal # 85, but the relay is not "clicking" when the seat switch cycles from activated to de-activated..........replace the relay.

{{gwi:323862}}

I failed to state that the testing should be with the key switch in the RUN position but with the engine NOT RUNNING.
KEY ON.......ENGINE OFF.

I may have mislead you about the OPS relay, looking again and reading the notes, if you follow the wire from the ignition unit back to the key switch terminal M for engine shorting is noted on the tractor connector plug at the bottom of that page. Following that through if you follow the wire from (M) it goes to the OPS which if not opened by the seat switch shorts out ignition if either brake is up or PTO engaged

You should be able to hear the relay click when the ignition is in the run position(engine not running)and the seat switch opens and closes. I would be careful with jumpering that seat switch since one side is 'hot' to the ignition switch (L).

If you don't already have one get a 12v test light and run through that schematic checking that you have 12V where it belongs you should see 12v at terminal 86 on the relay when the seat switch is closed. Another quick test would be to unplug the relay, if things work then or at least the motor keeps running with brake up and PTO switch pulled (PTO will not engage without relay but will test the switch) then it's either a bad relay or wire from the seat switch, you can connect the removed relay to a battery term 86 to one post 88 to the other and it should click.

If that is a 99 model I would be looking at all the connectors for corosion, I like to use waterproof silicone grease on things to keep out moisture, think you can get it at an autoparts or marine dealer.

Mownie,

I also thought that was a connection at first between 85 and D on the PTO sw, just love those old scanned diagrams with a few random pixles thrown in, to be honest it's hard to make out if that is 85, 86 or 88 from the picture so I will just call it the terminal with the green wire. Just so I don't mislead can you confirm what I said that it should run without the relay although the PTO clutch will not function.

***" you should see 12v at terminal 86 on the relay when the seat switch is closed."
NO! you will not be able to detect 12V at terminal # 86. Terminal # 86 is connected directly to the chassis ground along with terminal # 30.
You will be able to detect 12V on terminal # 85 when the seat switch is closed. but not on terminal # 86.
Or look at it like this: If you connect the ground clip of the test light to a ground in the normal fashion, and then touch the probe of the test light to the same ground part, the test light will not burn, that is why you can't detect 12V on terminal 86 in a routine test.

{{gwi:323863}}

Like I said the numbers are blured in the scan, so 85 is green wire from the seat switch and 86 is black to ground.

Just hope the OP can follow this. Thanks for the clear diagram & terminal #'s

***"so 85 is green wire from the seat switch and 86 is black to ground"***
That is correct.
This relay is an example of the now universally applied "Bosch 5 pin, 30 Amp relay".
You will find this relay (or a variant) in nearly every imaginable machine all over the world.
The relay has become so widespread that you can buy them at any auto parts house, usually for under $10. No need to try and find OEM. Take your old relay with you and the person at the counter will recognize it right away.
The relay costs so little, you can justify trying a new relay as a method of diagnosis, and feel no regret later if that was not the problem.

Wow... lots of info, been a little busy at work.
I'm in the process of going around the wires and switches.
As of now the seat switch seems to check out okay.
Just wanted to check in to let you know all your time spent on this post will not go to waste and is appreciated.
I will update as time permits.
Thank you
Joe

The relay is not showing power @ 85 also is not clicking when seat switch is opened or closed.
So maybe relay???
I have both ordered.
Still re- checking all grounds.
Joe

Joe,

12v for the relay comes from the seat switch via the ignition switch terminal 'L' so with key in 'run' position there should be 12v to terminal 'L' on the ignition switch and one term of the seat switch, closing the seat switch then sends +12V to the relay term #85.

So if there is NOT 12V to ground @ the terminal 'L' on the ignition switch, it's a problem with that. If there IS 12v at terminal 'L' and NOT at one of the two green wires for the seat switch there is a break in the wire between the ignition switch and the seat.

If their IS 12v @ one side of the seat switch and NOT at the other terminal when the seat switch is activated it indicates a faulty seat switch, test by jumping the connector then there should be +12 both sides of the seat sw connector and @ terminal #85 of the relay. If voltage IS present @ BOTH terminals of the seat switch (key in run , seat sat on or jumpered) AND NOT @ #85 there has to be a break in the wire from seat sw to the relay connector. Again you can test the relay by pulling it out, connecting it to a battery via terminals #85 and 86, it should click. Little more complex to test the relay itself but if you have a multimeter it would read zero Ohms between #30 and #87A when NOT energized and zero between #30 and #87 when energized, the relay is a remote control switch. Since the 'kill' function works it would seem that the ground to term #86 and #30 is good but it never hurts to check it. (you can check 'grounds' by putting the clip of your test light on the '+' battery terminal and then touching the probe to terminals to indicate 'ground' when the light is lit.

Howdy skipabeat, Pull the relay, if it keeps running when the clutch pedal is up, you kno wits the relay. That is a common hella relay for Off raod lights.

If its a green seat switch you cant disconnect it, if its grey you cant jump it.

Course if you got to ask, you all shouldnt be messing with safety systems--Not addressed to you skipabeat

Dave,

Yes with the relay removed it solves the problem or eliminates the brake and PTO switch. Think I suggested this eariler in the postings. Only way to tell for sure is checking +12V is present at the relay terminal #85 AND the relay works.

So just for my info a 'green' connector is a normaly open switch and a 'grey' one in a normaly closed seat switch?

"Don't ask ,don't tell" is a pretty messed up system of information flow IMHO.

Ask, get a explanition and learn works much better.

Yeah, I'm a bit confused by the remark "Course if you got to ask, you all shouldnt be messing with safety systems"
I don't know the intent of that, but my opinion is, "Of course you should ask if you don't know."
A lot of info flows to & fro on this forum as a result of questions (fact is, that is mostly what this forum is about, if you don't count the advertising). :^)

Alright.... everything pointed to the relay.
So when i got off work today my package of seat switch and relay were waiting for me.
Having the seat switch already off i exchanged the seat switches for the heck of it and nothing changed.
Changed the relay and it blew the 15 amp fuse.
After some words which i can't post here and a trip to the auto parts store for some fuses, i replaced the fuse and now it is running fine.
Its too wet to take it out for some serious cutting, so until that happens i won't be completely sure if my problem is over.
Thank you to EVERYONE for your time and help.
Happy mowing!
Joe

Joe,

Good to hear you got it running, should that fuse be a 30A as shown on the diagram? 15 will probably work for a while but will blow again if your working it to near capacity.

We'll be waiting for the update...............fuses don't blow just so they can hear the wind, there has to be an underlying reason. :^)

mownie,

"fuses don't blow just so they can hear the wind, there has to be an underlying reason"

Yup but if the PTO clutch and headlights are using 13-14 amps it could have just been a stressed fuse, they do weaken over time if used near max capacity. They after all are made to safely 'melt' and open the circuit so if you run a too small fuse you're nearly reaching that melting point and it will eventualy fail at less than rated amps.

If that replacement 15 amp fuse blows again in short order then there must be a wire shorting out someplace. If in fact the machine calls for a 30A fuse that is what I would use or at least a 25A one. Not sure if that is a two terminal plastic fuse or the older glass type fuse but in either case dirty connections, weak clips, or a weak spring in a inline fuse holder can create resistance and heat and cause a fuse to fail at less than rated amps.

I had that problem on a Yamaha motorcycle where the fuse block was notorious for weak fuse clips, overheating and blown fuses and eventualy failure of the clips due to heat stress, had to replace the block with aftermarket.

Well now, isn't this a sad day. I must be getting senile.
15 Amp fuse!!!!! Heck no, that is supposed to be a 30 Amp fuse! And like I said............gotta be a reason! The reason in this case was the fuse in there was only half up to the job. Get you a 30A fuse in there.

A 15 amp fuse was in it and I've never replaced it...as far as i can remember....
If you look on page 8&9 it states 15 amp fuse, on the other hand the schematic states 30 amp.
It does have the early 90's 2 prong fuses..... so i went with the 15 amp for now.

"I must be getting senile" Mownie, get in line I'm already at the counter!!
Joe

?????? Well, we were back to the land of confusion again on the "correct" Ampacity of the fuse, but I did some research that might straighten out this mess.
I will hazard a guess that 15 Amp is correct for the application based on 2 things.
(1) I have never "seen" a 30 Amp fuse in use in this duty on any make/brand tractor (highest I've seen as OEM was 20 Amp).
(2) Calculating the electrical load of this tractor: PTO clutch in good condition draws around 4 Amp, headlights (if 1156 bulbs) draw 2.1 Amp (each for 4.2 Amp total), fuel solenoid on carb might draw .25 Amp, OPS relay might draw .025 Amp. Total approx draw of slightly less than 8.5 Amp.
If the fuse actually blew when you were removing the old relay, there is the possibility that a loose piece of metal inside the relay may have shorted between term 85 (hot from seat) to a metal surface that is continuos to terminal 86 or 30 (grounded). The problems in that are that the key switch would have to be in RUN and the seat would have to be occupied (or the seat switch jumpered) for there to be current present at term 85 when the old relay was disturbed.
One final note here on the fact of a 30 Amp fuse being shown in the diagram: The diagram shown in the Ranch King OM is identical to a number of diagrams found in many Craftsman owner's manuals, and they all show the fuse as 30 Amp. Of course, the Craftsman IPL does not give the Ampacity of the fuse if you look further, only that it is a fuse.
So I have no idea where the draftsman drawing the diagrams came up with 30 Amp.
I retract my suggestion to replace the 15 A fuse with a 30 A rated fuse, and I apologize for even suggesting it in the first place.
Stick with the 15 A for safety's sake.

I have a similar, if not the exact same mower as Joe.

Kohler Command 20HP/46" Automatic Ranch King Pro
Model: 169003
Serial: 012199D001454
Mfg: ID #: RK20H46A

I bought it used last year and have used it once (last summer) and it seemed to work fine. I kept it outside (under tarp) all winter but have been unsuccessful in getting it started this summer. Upon putting in gas, I noticed it was running out onto the ground. I took the back end apart and noticed that the bushing was deteriorated and had slipped out of the tank. I bought a new bushing and fixed that problem. However the battery was dead so I replaced that also. Although the spark plugs were new as of last year, I grounded them against the engine and they are sparking. Also added oil to the appropriate level. The engine is turning over but will not even sputter to begin starting. Wondering what to do next. Also can't seem to find a manual for this anywhere on the web. Any help would be greatly appreciated.

You may just want to help it draw the new fuel up through the carb. Set the parking brake, remove the air filter and give it a spray of aerosol carb cleaner to act as a mild starting fluid) into the carb throat and crank it over- giving it an occasional burst until the fresh fuel gets through the system. It doesn't hurt to get the fresh fuel up through as much of the lines before hand- replacing lines that may feel spongy or hardened plus a new filter.