B7800 clutch safety switch

[curiousgeorge]

I finally used my 2006 B7800 for about 20 hours last week and found that once it warms up, if it stalls or I stop it for any reason, it will crank but not start unless I push the clutch back and forth a few times until something "catches" before the clutch is pressed all the way down.

When the tractor is cold, it seems to start right up by simply pressing the clutch all the way down one time.

Is this likely caused by a defective safety switch? If yes, I wonder where it is located on a B7800 please? I am hoping I would not have to disassemble too much stuff to get to it.

Thanks,

CuriousGeorge

 

[curiousgeorge]

if the problem would be a defective switch, would it be the one in the attached picture?

Thanks,

 

[Dave_eng]

if the problem would be a defective switch, would it be the one in the attached picture?

Thanks,

Looks like the switch.

I would be inclined to adjust it first before replacing it.

Is your clutch pedal's free play properly adjusted to be 1-1.5".

Adjust free play and then the switch.

Daave

 

[curiousgeorge]

Looks like the switch.

I would be inclined to adjust it first before replacing it.

Is your clutch pedal's free play properly adjusted to be 1-1.5".

Adjust free play and then the switch.

Daave

Thanks - I wonder if I have to remove the instrument cluster bonnet to get to it?

 

[Dave_eng]

Thanks - I wonder if I have to remove the instrument cluster bonnet to get to it?

I would be inclined to think you would access from underneath the tractor but this is an educated guess.

What about the clutch free play? If you find where to adjust this then the switch will be close by.

Dave

 

[curiousgeorge]

I would be inclined to think you would access from underneath the tractor but this is an educated guess.

What about the clutch free play? If you find where to adjust this then the switch will be close by.

Dave

I have a good 2 inches of free play on the clutch (maybe a bit more). I will try setting that to 1 inch first and maybe blow out the switch area and spray some lubricant on the switch. Does the transmission have to be in Neutral on the B7800 before I start? So far I have left it in M and just pressed the clutch down.

 

[Dave_eng]

I have a good 2 inches of free play on the clutch (maybe a bit more). I will try setting that to 1 inch first and maybe blow out the switch area and spray some lubricant on the switch. Does the transmission have to be in Neutral on the B7800 before I start? So far I have left it in M and just pressed the clutch down.

The pedal/switch interaction is independent of any gear selection

Dave

 

[Henro]

I must be missing something. My B2910 is the same tractor as the B7800, with some deluxe features.

If the engine turns over, it seems to me the safety interlock switch is functioning normally and your issue must be something else.

My guess is what you are experiencing is just coincidence, and unrelated to the clutch safety interlock.

 

[North Idaho Wolfman]

Like Henro said if it cranks then it's not the clutch switch.
It's more than likely a tired fuel cut off solenoid or a bad relay or OPC.

 

[curiousgeorge]

Like Henro said if it cranks then it's not the clutch switch.
It's more than likely a tired fuel cut off solenoid or a bad relay or OPC.

I adjusted the free play on the clutch and it still behaves about the same (although the clutch pedal feels a lot less sloppy) . It seems more likely to fire up when I start releasing the clutch. Last week I tried to just crank it over and over again for a few minutes (with breaks in between of course), and it didn't start until I pressed the clutch down and up while cranking.

I will try to remove the clutch switch to test it, but I have not been able to figure out how to remove it. It looks like it would be easy to get to if I remove the gas tank shroud, but I have not found instructions on how to remove it yet. Tried to remove a couple of 12MM bolts that secure that shroud from the bottom, but there seems to be a lot more of something holding it. If anyone has instructions on how to remove that switch I would greatly appreciate it.

 

[curiousgeorge]

Like Henro said if it cranks then it's not the clutch switch.
It's more than likely a tired fuel cut off solenoid or a bad relay or OPC.

Is the OPC the operator presence switch under the seat?

 

[North Idaho Wolfman]

No the OPC is a small computer under the dash.
With your last explanation, It's more likely bad wiring to the stop solenoid or a bad stop solenoid.

 

[curiousgeorge]

Like Henro said if it cranks then it's not the clutch switch.
It's more than likely a tired fuel cut off solenoid or a bad relay or OPC.

Thanks - I did have a problem with the solenoid shutting off one time so I just ordered a new Kubota solenoid. I had previously ordered an off brand and it didn't even fit so I returned it. I am learning that I should not even bother with off brand parts

 

[curiousgeorge]

Thanks - I did have a problem with the solenoid shutting off one time so I just ordered a new Kubota solenoid. I had previously ordered an off brand and it didn't even fit so I returned it. I am learning that I should not even bother with off brand parts

Well... replaced solenoid and still cranking but no start. Would a relay be next? I think the previous owner said he replaced the starting relay, but if he used a cheap knockoff relay I guess it could go bad soon. Tried moving the levers around and it looks like the cranking stops when I move the PTO lever and when I move the HST pedal back and forth, so I suppose the other switches are OK

 

[North Idaho Wolfman]

More than likely it's the OPC (controller), there is one relay in there but I do believe the relay controls the starter and it is cranking.

 

[whitetiger]

Here are a few pages that should help you out.

 

[curiousgeorge]

More than likely it's the OPC (controller), there is one relay in there but I do believe the relay controls the starter and it is cranking.

Thanks! I posted a separate question on the solenoid and it looks like I may have found the culprit... wires going to the relay touching each other. Not sure why pressing the clutch repeatedly would have ever helped start the motor, but after adjusting the clutch, the tractor has not started again. Either way, that clutch safety switch is on/off, so as others have said, it should not be the problem if the engine cranks at all.

 

[curiousgeorge]

Finally received new relay (Kubota OEM part T1060-33720)) and that was it! Glad I looked at the wiring as it needed some fixin'

I replaced the uninsulated wire sections, and wrapped+ covered the other wire bundles. AND I learned how to adjust the clutch and the brakes while I was at it.

It's a better tractor now and I'm a more informed tractor owner

Thank you all for your help!