PTO Interlock Stop Switch

[gwess 0]

Hello Everyone!

I have come to believe that my PTO Interlock Switch is bad and i need to order a new one but i cannot find the part # and i cannot locate anything similar online, Please help me get one these damn things.

 

I have come to checking the pto interlock switch because i am not getting any spark at my spark plug unless the ground wire on my magneto is not disconnected. leading me to think that i have a bad safety/kill switch somewhere.

 

upon checking the pto interlock switch I am not getting any continuity from the switch points when the pto is engaged and the little switch is open. I get continuity when the pto is not engaged and the switch is closed. - It is 4 prong switch with a line coming from the seat kill switch, clutch kill switch and i guess it acts as the pto kill switch as well.  

 

Everything else seems to be fine so far. The ignition is sending good continuity to all wires, the clutch switch is good, *(although now i cant figure which terminals go to which wire or if it even matters?) The seat kill switch has been removed and the wires tied together so that should be ruled out. Please help me to find the this switch.

 

I have gone through this entire motor and body trying to figure out how to get it going again. chainsaw season is coming and i need my lil wood puller. Also my lights are disconnected. That wouldn't break any currents or anything right? Any additional info would be awesome!

 

Thank you and I look forward to discussing things with you guys!

I am sorry. This is a 1983 GT 1142 with the 11hp Briggs. It has done many of amazing things just in the few years i have owned it. Remarkable little tractor!

[rmaynard 15,582]

I checked the Toro parts list for the GT-1142, and the part number is 98-2392.

 

[gwest_ca-(File Mod) 11,090]

That pto switch is two switches in one.

When the pto is OFF one pair of contacts are connected. That is for the starter circuit. Pto must be OFF to send power to the clutch switch which when closed sends power to the starter solenoid.

 

The other half off the switch works just the opposite. When the pto is OFF this pair is open - not connected. This leaves your ignition wire ungrounded so the engine will run. The other wire goes to the seat switch which is also open with the operator in the seat. Operator falls out of seat with pto ON the seat switch grounds the ignition and shuts the engine off.

 

Once you get the pto wires back on correctly try pulling the wires off the seat switch and isolate them so they can't get to a chassis ground. It should run like that but for testing purposes only.

 

Wiring diagrams

 

Make sense?

 

Garry

[gwess 0]

Thank you Maynard! I am terrible at finding stuff on line. I am even worse at finding it on Toro's website. 

Thanks for the info as well Garry! That is pretty much what my brain was trying to put together but you made it a lot easier to connect all the dots.

 

To be clear on checking the switch:

When PTO is not engaged and the interlock switch is depressed I get continuity on the left side of the switch, (over & under points) from what i believe is the clutch switch and the starter solenoid?

 

When i engage the pto i should get continuity on the right side of the switch between the over and under points, (i believe it is the seat switch and ground)?

 

Also does it matter if the lines on the clutch switch itself are switch or crossed? I can't figure which line goes to which point. There is only 2 points and lines. 

 

Also, I do not have a seat switch. It must have been removed. any suggestions on that? I have them connected together to create a closed circuit but you think i should take them apart? 

You don't think the headlight wires make any difference to anything right? My headlamp connectors rusted and broke off and now the wires have no real good place to go. Any thoughts there?

[gwest_ca-(File Mod) 11,090]

You have it figured out.

 

It does not matter which wire goes to which terminal. As long as that pair are on the correct side or half of the switch.

 

Keep the wires for the seat switch separated and wrap with tape to make sure they don't contact any metal or each other. That will shut the engine off. Once you get it running you can always get the correct switch and reinstall. It is a good safety feature.

 

Tape up the headlamp wires so those connectors can not short to the chassis. That will blow a fuse. You can always get lights later.

 

The important detail with the B&S ignition is do not allow any battery power into that ignition wire. 

Feel free to ask questions if you are not sure.

 

Garry 

[gwess 0]

Well i am not getting any reading on the right side of the pto switch there for i think the seat & ground terminals are not connecting. I will try to order a new switch tomorrow and i will look into a new seat switch as well. 

 

I am not sure i totally follow you on the last note there Garry. Do not allow power into the ignition wire from the battery. Why don't i want power from the battery to the ignition wire and how do i keep it from getting there? and what ignition wire?  Ignition wire from seat switch or lights?  Do i keep it from crossing by removing the connectors from the switch points? 

 

Also quick question. There is a blue wire that runs to the front of my Briggs and grounds onto the throttle body. It shares the same grounding point as the ground from the magneto. Any idea what this wire is?

 

Thank you very much for your assistance. I really appreciate your time. This is awesome. 

[Howie 892]

The briggs engine has a magnetic ignition which requires no current from the battery. If 12 volts go to it the coil will be history. Just do not get the wires on the safety switch crossed up. If in doubt check for voltage with the kill switch uncooked from the coil.

[gwest_ca-(File Mod) 11,090]

That blue wire is the "ignition" wire and the one that we do not want any battery voltage to get to. I suspect it joins the magneto wire at an insulated block on the engine for convenience.

 

This ignition system is self powered. With the ignition wire not grounded it works. Ground the ignition wire and it disables the ignition.

 

That is why the blue wire goes to the ignition switch and on to the seat switch through the pto switch - either one of the three can shut the ignition off depending on the condition.

 

If you wanted to make sure the ignition works you could disconnect the blue wire at the engine and that eliminates the tractor wiring. It should run. If it does to shut it off use a jumper to short the magneto wire at the engine to ground.

 

Garry

[gwess 0]

Alright gentlemen. 

I ensured that the wires that should have gone to the seat safety switch are taped separably and not touching anything. I purchased a new PTO Interlock switch, installed it and now I am getting nothing, not even a click from the ignition. I jumped the solenoid just for fun to see if it would turn over and the engine turns over great but no fire. So i fear that the original problem of the spark plug not firing, while the magneto is grounded still exist and now I added the issue of not getting any power through the ignition.

 

I need to find a good wiring diagram showing what wires should be connected to what terminals and such and then ensure that they are connected correctly. I did not check the new pto switch for continuity but I would like to assume it is good. I plan on taking the ignition switch back off and retesting for continuity, which should be good since i had just checked it, and also checking to ensure all wires are secured to their switch points. After all wires and points are checked the ignition should then send power to the solenoid and then I will pull the plug and see if i am getting spark from the plug with the magneto grounded or not. 

 

To be clear on the seat safety switch. If i am in the seat the seat safety switch, if i had one, points would be open and that is why i should have the two seat safety switch wires taped separately so that the circuit runs even though there is no safety switch. Having the wires taped together acts like i am out of the seat killing power to the ignition. 

 

I have the owners manual showing the wiring diagram but if anyone has any other materials or knows any other outlets that can help me out it would be much appreciated.

I have rebuilt the carb, polished the heads and reseated the valves. I have gone through all the wire connections and cleaned them up. I installed a brand new magneto and now a new pto interlock switch. I have a lot of work this lil tractor needs to do now and even more soon and i still have catching up to do on some mowing.

 

I do not want to give up and take it into the shop!  

[Save Old Iron 1,566]

To be clear on the seat safety switch. If i am in the seat the seat safety switch, if i had one, points would be open and that is why i should have the two seat safety switch wires taped separately so that the circuit runs even though there is no safety switch. Having the wires taped together acts like i am out of the seat killing power to the ignition. 

 

Baseline, if the kill wire to the magneto is connected to battery negative ("ground" if you must), the magneto cannot produce a spark and the engine will either

 

1/ not start

or

2/ shut off if already running.

 

 

NEVER EVER apply +12 volts to the kill wire. The primary windings in the ignition transformer in the magneto will burn out. The windings in the magneto are about the same size as #00 steel wool. Apply battery voltage directly across a wad of steel wool and see what happens - and how quickly it happens!

 

Consider the kill wire is grounded by one of two methods.

 

First is the ignition switch. The "M" terminal on the ignition switch is grounded when the ignition switch is in the off position. The kill wire from the mag should be attached to the "M" terminal of the ignition switch.Simply put, when you wish to turn off the engine, flip the ign switch to OFF, the "M" terminals shorts the mag to ground - no spark.

 

Second method to kill the magneto is thru the PTO switch / seat switch combination.

 

Let's say the engine is running. Two different scenarios are possible now.

 

The PTO is disengaged (no dangers to the operator from spinning blades,etc). The manufacturer wires the kill function to a "don't care" if the operator leaves his seat. The "don't care" is accomplished electrically by the kill wire being attached to one of the PTO safety switches which open circuits when the PTO is not engaged. The other wire from this same PTO switch goes to the seat switch which then goes to ground.

 

Sooooo, if the PTO is disengaged, the kill wire can never be grounded by the operator leaving their seat because the open PTO safety switch has disconnected the seat switch from the kill circuit. The only way to ground the kill wire is .... by the ignition switch.

 

Second safety scenario,

 

The PTO is engaged (danger exists to the operator if they leave the seat). The manufacturer wires the tractor to watch the seat switch. This is accomplished by electrically closing the PTO safety switch connected to the magneto kill wire. If the operator leaves the seat with the PTO on, the seat switch grounds out and applies the ground thru the closed PTO switch to the kill wire attached to the same PTO switch. Kill wire is grounded, so the engine cuts out.

 

If you have the seat switch permanently taped (electrically) open, there is really no longer any (electrical) need for the PTO safety switch at all. Safety is now the primary concern. How is the tractor going to know you left the seat with the PTO engaged, putting yourself in danger?  The engine will happily keep the mower blades moving to chop off appendages, catch snow thrower augers on loose snow suits, or keep the hot engine running as the tractor lies on top of you, both assend up overturned in a gutter. Not something I can endorse as a fun time. Guess it goes without saying bypassing safety switches is not something I support.

Edited September 23, 2014 by Save Old Iron

[gwess 0]

Alright fellas,

 

I am checking out the electrical at the moment. I have pulled the ignition setup and some things were funny, a couple of disconnected wires. So, I need to put it back together. I traced the lines and found one of the wires to the seat switch had a tear in the wire casing and was probably shorting out against the frame. So i fixed the tear and now I need to get it back together. The two seat wires: One has an orange stripe on it that goes to the small top right terminal on the pto switch. The other wire is solid black and I am not sure where it goes. The wire diagram shows one wire going from the seat switch to the pto switch and then to the ignition, i assume this is the wire with the orange stripe. In the diagram the other wire is shown as a ground leading from the switch to nothing. On my end it definitely has a connector and goes somewhere. To the ground on the ignition?  

 

Also, off of the ignition i have a wire that has a red stripe on it that goes to the amp meter. The other wire was disconnected and I am not sure which one goes to that terminal. The wire that is solid orange and goes to the hour meter? 

 

And then i have a wire that has a pink stripe on it that comes out of the 15amp fuse but is not connected anywhere else. Wheres this bad boy go? it seems to short to reach the ignition switch but obviously goes to same main function. 

 

Here is a good one. The connector that hooks up the ignition is missing a wire that should connect to the R terminal. My whole quest here has been to discover which wire goes here. Previously when i checked the ignition switch I had stuck the orange wire in there and now I think i am learning that the orange wire is accessory and what i suppose should be the rectifier. So where does this rectifier wire come from on the engine? Ok, I think I am getting here. The rectifier wire is the wire coming from the 15 amp fuse? and should go into that slot hooking up to the R terminal on the ignition switch? oh wait no because the fuse wire cant reach the ignition. 

 

Note. I do have a horn on here. it does seem a bit funny. Would it simplify things if i disconnected it? Or leave it because its there and it works? I think i would like to go ahead and disconnect the hour meter as well, it doesn't and probably because the wire coming from the reset button next to the meter isn't connected to anything. 

 

I think i am going to hold off until i get some directions from one of you guys. Thank you very much I really appreciate the feedback. I'm dang close.

I have a few small piles of dirt leftover from drilling a well and i would like to use the lil tractor beast to push it back down into the catch and intake holes i dug. Then its on to grass and then pulling water cart and firewood. 

[gwess 0]

Alright so the orange wire that goes to the hour meter goes to the A (accessory) point on the ignition switch. I had it right the first time i suppose. It was the A terminal that the connector was missing not the R

[gwess 0]

ok so i think i have found a home for everything besides the 15 amp fuse wire coming from the fuse. Any thoughts?

Also, I only have 2 wires on my magneto. The spark plug wire and the ground wire. 

[gwess 0]

Alright guys. I think all i need to know is where does this fuse wire go? One wire goes to the solenoid but how about the other? I can't find where it goes. I assume the ignition but I have no spot for it. It looks like it should go the ground terminal but that's where I have the seat kill switch hooked up to. It and the solenoid. 

[gwess 0]

Sorry for all the post but i should also not that i am missing a wire that goes on the amp meter, the right terminal. So im sure i have something mixed up. 

[gwest_ca-(File Mod) 11,090]

The wire that is presently on the ammeter probably powers the the ignition switch. 

 

The fuse wire is on the battery cable side of the solenoid so it is hot all the time. The fuse powers the other side of the ammeter.

 

Garry

[gwess 0]

So the wire i have on the amp meter needs to hook to the ignition switch to power it? What terminal would it go to? or when i hook the fuse wire to the amp meter that will allow power to the ignition?  I will try hooking the fuse to the amp meter after work and see what happens.

[km3h 543]

See if this helps. I strongly advise you to download the books for this tractor. They are available both on this site and on the Toro site. Having the right documentation is paramount to diagnosing any problem with your tractor. If you click on the inserted picture it will enlarge for a better view.

 

 

This shows the circuit with the ignition switch in the off position       

 

This is the same circuit with the ignition switch turned on.                 

 

This shows the circuit with the ignition on and the PTO engaged.      

 

 

[Save Old Iron 1,566]

Let's step back for a second. Gus is asking about wiring to an ammeter but the manuals and schematics we are posting DO NOT SHOW AN AMMETER,

 

So the wire i have on the amp meter needs to hook to the ignition switch to power it? What terminal would it go to? or when i hook the fuse wire to the amp meter that will allow power to the ignition?  I will try hooking the fuse to the amp meter after work and see what happens.

 

One terminal of the ammeter should go to the "B" terminal on the ignition switch.

The other terminal of the ammeter connects to the battery, either directly or thru the battery terminal on the starter solenoid.

 

 

 

 

Gus, one of the recomendations I would make is not to go strictly by wire color codes. If you post a "where does this wire do?" type question, it would be helpful to rephrase the question to something like

 

"I have a wire that is connected to the small terminal of the starter relay - where should the other end of this wire be attached?"

 

This allows folks to recognize the FUNCTION of the wire and make the proper recommendation as to where the "other end" attaches.

 

Keep asking questions - you will get this done correctly.

Edited September 27, 2014 by Save Old Iron

[gwess 0]

Hey guys,

Just wanted to let you all know I did get it running! Thanks to your help! All I had to do was hook that 15 amp fuse wire up to the end of the amp meter. I believe the initial problem was the wear in wire causing it to ground out on the body. All your help was great. It wasn't your job and no one was making you do it but you guys went out of your way to provide thoughts and share knowledge and that is highly honorable. You all are scholars and gentleman and I truly appreciate your help. I will continue on and do awesome things thanks in part to you.

[km3h 543]

Glad to hear that your problem is solved.