Safety Switch Issue

[BHpa 10]

I have a WH 310-8.  I think I'm having an issue with the safety-cutoff switch - the small toggle switch under the seat.  Does anyone know if I can safely bypass the switch by cutting the two wires and connecting them together with a wire nut, or do I need to try and find a new switch? 

 

Or better yet, does anyone know how to test the switch to see if it's still viable before I go to that effort?  I'm not 100% sure this is the problem, but it seems to be.  

 

Thanks in advance for any advice!

[gwest_ca-(File Mod) 12,353]

Guessing this is the switch. It controls the magneto ignition so try it with the wires disconnected. It is a very important switch to have working.

Perhaps the seat is not opening the switch. Can you adjust the switch height?

 

[squonk 47,384]

Those micro switches fail just by looking at them. Most likely junk.

[ri702bill 12,478]

8 minutes ago, gwest_ca said:

It is a very important switch to have working.

Yup - that says it all.......

[Handy Don 16,948]

Post a picture of your switch and we can be more helpful. 

[kpinnc 18,745]

1 hour ago, gwest_ca said:

Guessing this is the switch. It controls the magneto ignition so try it with the wires disconnected. It is a very important switch to have working.

 

I do not know what year model your 310 is, but on the 1987 models the seat switch only engages if the PTO is also engaged. 

 

I had issues with mine once that actually turned out to be one of the two PTO switches. One is part of the interlock for the PTOs engagement, one is for the starting interlock where the PTO must be disengaged. The switches were stacked together, with one providing an open circuit while the other provided a closed one. 

 

Having your backside firmly planted when a snow blower, mowing deck, tiller, or other powered attachment in motion is pretty important. Very few of the members here would recommend removing it. 

[JCM 11,260]

1 hour ago, kpinnc said:

 

 

Having your backside firmly planted when a snow blower, mowing deck, tiller, or other powered attachment in motion is pretty important. Very few of the members here would recommend removing it. 

[BHpa 10]

Thanks all.  

 

The switch looks identical to the one posted above by gwest_ca.  I agree that it's a good safety switch and I'd like not to bypass it, but I figured if I could bypass it and get the tractor started then I could narrow the issue down for sure.   KpinNC - any suggestions on how I can narrow the issue down between the seat switch and the PTO?  

 

I've been having an issue starting the mower on and off for a bit.  I thought it was the battery.  But the other day even after I hooked my jumper up to it I still couldn't get it to turn.  That's when I noticed the safety switch was stuck (oddly enough in the depressed position).  When I wiggled it loose and then sat on the mower it started right up.  Similar thing yesterday.  Mowing fine then stopped for a quick bite to eat.  When I came back out it wouldn't start.  I checked the switch and it was stuck in the depressed position.  When I unstuck it, then sat down it started up just fine.  Had to shut it off one more time mid-mow and that's when it failed to start no matter what I did.  

 

One question, though.  My switch only has two wire connected in it.  It looks like there is space for 3.  Should there be three?  Could this be the problem?

 

Sorry for just tossing out lots of info, I'm mostly just thinking out loud here since I'm not very experienced with mechanical troubleshooting. 

 

Thanks!!

[kpinnc 18,745]

18 minutes ago, BHpa said:

KpinNC - any suggestions on how I can narrow the issue down between the seat switch and the PTO?

 

I'm fairly sure the wiring diagram is in our manuals section. You need to search on your specific model and year. The tag under the seat will have a part and serial number for your machine. 

 

For my 1987 model 310, the clutch switch, PTO, and low oil were required to be closed to allow starting. 1987 was the first year of the Magnum 10 engine, so the entire ignition system was different. 

 

In other words the clutch had to be depressed, PTO disengaged, and the oil float had to all be in the proper position to send 12v to the starter solenoid.

 

The seat switch had no affect until the engine was running and the PTO was engaged. It was a completely different interlock circuit. 

[Handy Don 16,948]

30 minutes ago, BHpa said:

One question, though.  My switch only has two wire connected in it.  It looks like there is space for 3.  Should there be three?  Could this be the problem?

 

I can offer some info:

- the switch has both normally open (NO) and normally closed (NC) contacts (they are usually labeled with tiny embossing on the switch body). From that, you can see which two are being used by the connector. 

- I cannot say, without checking the wiring diagram for your model, which contacts your tractor uses. Variation comes from magneto vs. coil ignition and whether or not there is a “safety” relay as part of the ignition system.

- the switches do fail over time, mainly from contamination with dust and/or moisture

 

All of that notwithstanding, the seat switch does not normally prevent starting by itself. Rather, it works in sequence with one of the PTO lever position detector switches. Only if the operator is not seated and the PTO is engaged will the system stop (or prevent starting) the engine. 

Edited May 29 by Handy Don

[BHpa 10]

Thanks.  I was able to pin down the year - 1990.  And found the wiring diagram.  I'm not certain, but maybe I'm missing a wire.  The switch seems to have Red, Orange, and brown going into it.  Mine only has Brown and orange.  I guess tonight I'll try and dig around and see if I can find a loose red wire in the loom.  

 

Handy Don, - that makes sense about needing the PTO AND being unseated.  I guess I'll also dig around and see what I can figure out with the PTO switch too. 

 

Thank you all.  I'm sure I'll probably be back with a few more questions after I get some time to fiddle with it. 

[gwest_ca-(File Mod) 12,353]

These should be the correct wiring diagrams. Two wires to the seat switch.

 

[Handy Don 16,948]

16 minutes ago, gwest_ca said:

These should be the correct wiring diagrams. Two wires to the seat switch.

 

Hi, gwest, I tried to download these documents and there is a format issue. Can you please check them out?

Thanks!

[953 nut 67,401]

On 5/29/2026 at 3:18 PM, BHpa said:

 The switch seems to have Red, Orange, and brown going into it.  Mine only has Brown and orange.

If it were a 312-8 there would be a wire from the seat switch to an indicator light panel, the 310 doesn't have one.

On 5/29/2026 at 8:58 AM, BHpa said:

I'm not 100% sure this is the problem, but it seems to be.  

What is the problem, you never told us what isn't happening      The seat switch only comes into play if the PTO is in operation. Low oil level is another thing that can prevent the starter from working.

Edited June 3 by 953 nut
fat finger

[gwest_ca-(File Mod) 12,353]

2 hours ago, Handy Don said:

Hi, gwest, I tried to download these documents and there is a format issue. Can you please check them out?

Thanks!

I just clicked on the fuzzy picture in the link and it takes me to the home page of the file. You can view the wiring diagram by clicking on it or download the 5 page file of detailed wiring which also downloaded fine.

???????

[Handy Don 16,948]

2 minutes ago, gwest_ca said:

I just clicked on the fuzzy picture in the link and it takes me to the home page of the file. You can view the wiring diagram by clicking on it or download the 5 page file of detailed wiring which also downloaded fine.

???????

Yep, now it works like a charm! Thank you. 

When I first downloaded it came with a “.download” suffix and MacOS treated it like a package that it couldn’t open. Oh well.

[BHpa 10]

17 hours ago, 953 nut said:

If it were a 312-8 there would be a wire from the seat switch to an indicator light panel, the 310 doesn't have one.

What is the pr4oblem, you never told us what isn't happening      The seat switch only comes into play if the PTO is in operation. Low oil level is another thing that can prevent the starter from working.

Long story short - it won't even begin to turn over.  

 

I thought it was a battery issue since I solved it a few times by jumping it, but put in a new battery today and nothing.  It's not clicking or anything like if the starter was bad.  In a couple previous instances I was able to get it started after I noticed the seat switch was stuck in the depressed position which admittedly seems odd to keep it from starting, but when I freed it up it started.  This is what caused me to think it's a seat switch issues.  

 

I tried removing the seat switch and using a spare wire to jump the orange and black wires together through the housing but it didn't make any difference - still nothing.  I'm not entirely sure it made a good connection, but I think so. 

 

One other note, this time it died more or less mid-mow.  First I stopped to grab a quick bite of dinner and it wouldn't start.  That's one of the times I toggled the stuck seat switch and then it fired right back up.  Then about 30 min later I stopped to move some things into the garage and it wouldn't start back up. Checked the sweat switch and everything.

 

I'm really at a loss.  If it was the PTO switch you'd think it would still work if I was sitting on the mower.  

I checked the few fuses I saw and they're good.  

 

I'm at a loss for what to check next or where to start digging.  I appreciate all suggestions.

 

Thanks.

Edited May 30 by BHpa

[Handy Don 16,948]

If your tractor is still wired per the diagram, connecting the two seat switch wires together is telling the system that you are NOT in the seat.

 

There is also a clutch interlock (the switch is near the clutch pedal).

So PTO disengaged and clutch depressed should permit starting. If either of these are non-functional or not in the correct position then you won’t even get a click of the starter. 

 

There are two switches that detect the PTO lever position.

It PTO is disengaged and the clutch depressed, the starter can work

If PTO is engaged and the operator is not in the seat, the engine dies.

Edited May 30 by Handy Don

[BHpa 10]

So I ran down a few leads and it appears that it is a bad solenoid.  I jumped the two terminals of the solenoid with a screwdriver and it turned over, so I'm guessing that's the part I need to replace.  Apparently the not starting and stuck seat switch were inconsequential - sorry about that.  I'm gonna order a solenoid and install and hope it fixes the problem.  If not, I'll be back asking more question.  I truly appreciate all the input from everyone. 

[953 nut 67,401]

Place your shift lever in neutral and block the tires so the tractor can't move. Now take a small jumper wire from the battery "+" terminal to the small purple wire on the solenoid. If the starter turns over the solenoid is working.

[BHpa 10]

So I replaced the battery and the solenoid and still no luck, I can't get it to turn over.  If I use a screw driver to bridge the two poles of the solenoid it starts to turn over, so it doesn't seem to be a starter issue.  Any clue as to what it could be or what lead I should follow next?  

[gwest_ca-(File Mod) 12,353]

Did you download the 5-page wiring file?

One of the diagrams is for the starter circuit. Just follow the wires to the starter solenoid.

The oil level is not low is it? The low oil level switches seldom fail.

If  the low oil level switch in the oil pan needs to be removed there are special instructions to remove it without damage. Let us know and will post a link to the info.

[953 nut 67,401]

11 hours ago, BHpa said:

I replaced the battery and the solenoid and still no luck,

Stop replacing parts hoping for luck and do a bit of diagnostic work rather than wasting money on parts you probably didn't need.

Why won’t my starter turn over from the key switch?

Lets take a logical step by step inspection of your starter problem.

Is your PTO in the ON position, a wheel horse will not start with the PTO on.

Have you had the battery load tested at an auto parts store?

Have you cleaned and tightened all electrical connections including grounds?

Are all fuses good and fuse holders cleaned?

If these have all been done, we can check components of the starting system as follows; don’t skip a step or you may miss the problem.

Be sure the transmission is in neutral and the parking brake is set.

Take a pair of automotive jumper cables and connect the black cable to your battery  "-" and a good clean spot on the engine. Now connect the other cable to the large post on the starter and touch the other end to the battery "+" terminal, does the starter turn over? If the starter turns over the battery and starter are good. If it didn't turn over try the same steps with the battery in your car/truck, if that cures the problem then the "good" battery wasn't so good.

Presuming the starter turned over move the jumper wire from the starter post to the other end of the wire going to the starter which is one of the large posts on the solenoid. If the starter turns over when the battery is touched by the jumper as before then that cable is good, if not you have found your problem.

Presuming the starter turned over move that jumper to the other terminal of the solenoid, connect the other end to the battery and use a small piece of wire to temporarily connect the battery "+" terminal to the small terminal on the solenoid, this should cause the solenoid to close and the starter to turn over. If not, the solenoid is probably the problem.

If this was successful remove the large jumper cable and use the small jumper wire to the small terminal of the solenoid, the solenoid should close and the starter turn over. If not the cable to the battery is the problem.

Presuming all of these have been successful remove the black jumper wire and repeat the small jumper to small terminal, if the starter turns over the ground is good.

If all of these components test good then remove your ignition switch, be sure the transmission is in neutral, parking brake on, clutch depressed and PTO off. Use a small jumper to connect the terminals that were connected to the “B” and “S” terminals of the ignition switch. If the starter turns over then the PTO switch and other safety switches are operating properly and your ignition switch may be bad

[BHpa 10]

11 hours ago, gwest_ca said:

Did you download the 5-page wiring file?

One of the diagrams is for the starter circuit. Just follow the wires to the starter solenoid.

The oil level is not low is it? The low oil level switches seldom fail.

If  the low oil level switch in the oil pan needs to be removed there are special instructions to remove it without damage. Let us know and will post a link to the info.

 

Yep.  Looked at the wiring guide as best as I could understand it.  Things seem correct.

 

Oil level is fine and no issues there.  But I have no clue how to tell if it's that switch.

[BHpa 10]

19 minutes ago, 953 nut said:

Stop replacing parts hoping for luck and do a bit of diagnostic work rather than wasting money on parts you probably didn't need.

Why won’t my starter turn over from the key switch?

Lets take a logical step by step inspection of your starter problem.

Is your PTO in the ON position, a wheel horse will not start with the PTO on.

Have you had the battery load tested at an auto parts store?

Have you cleaned and tightened all electrical connections including grounds?

Are all fuses good and fuse holders cleaned?

If these have all been done, we can check components of the starting system as follows; don’t skip a step or you may miss the problem.

Be sure the transmission is in neutral and the parking brake is set.

Take a pair of automotive jumper cables and connect the black cable to your battery  "-" and a good clean spot on the engine. Now connect the other cable to the large post on the starter and touch the other end to the battery "+" terminal, does the starter turn over? If the starter turns over the battery and starter are good. If it didn't turn over try the same steps with the battery in your car/truck, if that cures the problem then the "good" battery wasn't so good.

Presuming the starter turned over move the jumper wire from the starter post to the other end of the wire going to the starter which is one of the large posts on the solenoid. If the starter turns over when the battery is touched by the jumper as before then that cable is good, if not you have found your problem.

Presuming the starter turned over move that jumper to the other terminal of the solenoid, connect the other end to the battery and use a small piece of wire to temporarily connect the battery "+" terminal to the small terminal on the solenoid, this should cause the solenoid to close and the starter to turn over. If not, the solenoid is probably the problem.

If this was successful remove the large jumper cable and use the small jumper wire to the small terminal of the solenoid, the solenoid should close and the starter turn over. If not the cable to the battery is the problem.

Presuming all of these have been successful remove the black jumper wire and repeat the small jumper to small terminal, if the starter turns over the ground is good.

If all of these components test good then remove your ignition switch, be sure the transmission is in neutral, parking brake on, clutch depressed and PTO off. Use a small jumper to connect the terminals that were connected to the “B” and “S” terminals of the ignition switch. If the starter turns over then the PTO switch and other safety switches are operating properly and your ignition switch may be bad

 

Thanks, this is helpful, I appreciate the run down.  To be fair, I wasn't really guessing at the solenoid as much as it was recommended as a potential issue by a guy who repairs wheel horses after a few checks.   But to run down the list:

 

- PTO is in the off position.  

- new battery - I didn't have the old one load tested, but I replaced the old one because it was 7 yrs old and wasn't really holding a charge and I was limping through the start of the year with jumping it each start anyways.   So I figured this was as good of a time as any.

- I've cleaned and tightened every electrical component I can access and am aware of.  

- checked all fuses.

- I will attempt these other tests tonight when I'm done work. 

 

I will add and I'm not sure where this falls in the last 3 or 4 tests, but when I connect the two posts of the solenoid (bridging them with a screw driver) the starter begins to crank. I haven't held the screw driver on long enough to get it to start because of the sparking, but I did notice that the starter cranked at that point. 

 

Again, I appreciate all the advice.

 

 

 

 

T