B7800 won’t start

[Gto19]

Hey guys
I have a 150 hour b7800 tractor that is a garage queen . I mainly use it to mow my field. I turned it off and now it won’t crank . Lights all come on though . I checked all the safety switches except the clutch safety switch because I don’t know how to get to it . I see the white connector though . I can easily start the tractor with a long jumper wire I made to go to the positive side of the battery to the starter .It will turn off with the key . Any help before I call a mechanic?


I’ve also tried rocking the forward reverse pedal to its sweet spot with no luck

 

[CH4Ohio]

Track down that clutch safety switch before you call a mechanic. Follow the linkages.

 

[Gto19]

Track down that clutch safety switch before you call a mechanic. Follow the linkages.

Yes I can see the clutch safety switch. It’s a plunger style like the other three

 

[ronjhall]

Are the PTO levers in off position? That’s the first thing I check when I have no engine turnover when key is turned to start position.

 

[CH4Ohio]

Ok. You said you didn’t check it. Sounds like you have now??

Mine had to be adjusted because it had backed out a little. Pretty easy fix if that’s the problem.

 

[Gto19]

Are the PTO levers in off position? That’s the first thing I check when I have no engine turnover when key is turned to start position.

Yes
Always the first thing i check

 

[Gto19]

Ok. You said you didn’t check it. Sounds like you have now??

Mine had to be adjusted because it had backed out a little. Pretty easy fix if that’s the problem.

I haven’t checked the switch with my volt meter because the plug is buried but I can see the plunger part of the switch and it’s making contact with the clutch bar when I engage it

Thanks guys

 

[number two]

Wow!
An 150 hour B7800 is a garage queen indeed!
Good Luck with your diagnosis!
Could it have the OPC(Operator Presence Controller)system?
Just a thought,

 

[CH4Ohio]

I haven’t checked the switch with my volt meter because the plug is buried but I can see the plunger part of the switch and it’s making contact with the clutch bar when I engage it

Thanks guys

Did you try pushing up on the plunger with a flat screwdriver, etc. to be sure it's being actuated far enough to close the switch? Mine wasn't and I simply had to loosen the adjusting nuts and move the switch a little closer to the linkage. It was getting "pressed", but not enough to close the switch.

Worth verifying . . .

 

[Little Red Tractor]

Let us all know what you do find. Sounds like it will be that clutch switch.

 

[Fxfymn413]

Bounce up and down on the seat; "snap" the PTO lever a couple of times; drink more beer to be heavier for the seat switch.

 

[CH4Ohio]

You can also get the plug off the back of that clutch switch and jump it to see if it starts. Just another way to check the switch.

It might actually be bad and needing replaced instead of adjusted. Seems unlikely though given the hours, etc.

 

[SDT]

Hey guys
I have a 150 hour b7800 tractor that is a garage queen . I mainly use it to mow my field. I turned it off and now it won’t crank . Lights all come on though . I checked all the safety switches except the clutch safety switch because I don’t know how to get to it . I see the white connector though . I can easily start the tractor with a long jumper wire I made to go to the positive side of the battery to the starter .It will turn off with the key . Any help before I call a mechanic?


I’ve also tried rocking the forward reverse pedal to its sweet spot with no luck

I have a similar but intermittent problem with my 675 hour B1750. Occassionally, it will not crank after turning the key to start. It has been very difficult to diagnose as it is quite intermittent and I have been dealing with the issue for 4 or 5 years.

Not normally one to throw parts at a problem, I have resorted to doing so in this case as I have repetitively convinced myself that I had found the problem.

So far, I have replaced the starter, solenoid, clutch interlock switch, ignition/start switch, both battery cables, fuseable link, and, of course, battery (needed due to age), but the problem persists. I've also shorted out the small, NLS, harness between the ignition/crank switch and cranking circuit without effect. I've been unable to use a voltmeter to find the voltage drop because it always works as designed when I've tried to do so.

I've waited patiently expecting a hard failure rendering diagnosis possible but after 4 or 5 years, it remains intermittent.

Someday....

 

[number two]

Of course everything works fine when the repairman arrives!

 

[bowenskye]

Have you tested the voltage at the start terminal on your key switch?

 

[dmdmatt]

Double check what you call the forward/ reverse pedal. There is a rod with a spring that activates the safety switch. It may need to be lubed if it’s hanging up. It happened on my B3200. It’s independent of the pedal position.

 

[7Jetboy]

Hey guys
I have a 150 hour b7800 tractor that is a garage queen . I mainly use it to mow my field. I turned it off and now it won’t crank . Lights all come on though . I checked all the safety switches except the clutch safety switch because I don’t know how to get to it . I see the white connector though . I can easily start the tractor with a long jumper wire I made to go to the positive side of the battery to the starter .It will turn off with the key . Any help before I call a mechanic?


I’ve also tried rocking the forward reverse pedal to its sweet spot with no luck

My B7800 had a problem with the fuel cut off switch. You can hear it 'click' (energizing the switch) when you turn the key to the start position. If that doesn't make contact it won't 'click' and cuts off the fuel to the engine and it'll turn over but not start. This switch cost about $150 and is located by the key switch under the RPM indicator. And yes, everything else had power.
It may not be your problem though as you were able to start it by jumping it. Just make sure you hear that 'click' when you turn the key.

 

[DieselBound]

I'll cast my vote for the clutch safety switch. The one on my tractor (1800+ hrs) has been marginal for as long as I can remember: there's a tang that pushes down on the switch and it tends to bend- it's too much of a pain to get to so I've left it as-is because that's a security "feature" as no one is going to be able to start it and steal it. I have to do rapid stomps on my clutch pedal as I turn the key and eventually it hits a sweet spot. The brake pedal switch on my Kioti is similarly possessed (also have to do rapid stomps): this acts up only infrequently so I just live with it.

 

[charlessenf]

I can't tell you the number of times I've panicked because my B7800 was 'dead on the paddock' nly to discover I'd accidentally caught one of the control handles with my jeans, jacket, coat, belt or bottom getting in, on or off the thing.

Based upon the responses so far, I may not have been the first forlorn farmer to experience such a failure.

There's a manual and parts diagram online somewhere - here's an old link I saved last time I looked for one:

Index of Kubotabooks/Tractor Parts Manuals/

If you've "neutral'd" all the levers a belt can pull on, the clutch kill switch is the best guess and the parts diagram the best map to it I can think of.

But I can't always think of everything, so I would look in the Trouble Shooting section of the Owner's Manual.

Or call Brett @ Blue Ox Tractors & Farm Mach (828) 584-9977 / (828) 391-7889 (cell) - Tell him Charles sent you and said to say Hello to Fay.

 

[charlessenf]

Wow!
An 150 hour B7800 is a garage queen indeed!
Good Luck with your diagnosis!
Could it have the OPC(Operator Presence Controller)system?
Just a thought,

Yep, Momma done told us it was a poor soldier what looked behind him - maybe a poor farmer what forgets to look below?

Imagine all this time and he was sittin' on his problem?!