Kubota 7800 won't start

bmckillip · Sep 22, 2009

Hello all- I have owned this tractor for about a year now (no problems whatsoever until now). Recently,the past several times that I have used the machine I have experienced some difficulty starting it. Lately when trying to start it nothing happens when the key is turned to the start position. I have narrowed the problem (I think) to a safety switch problem as the starter and battery are both working fine (this machine has only has 140 hrs. on it). I have located two safety switches on the seat and both appear to be working OK (tested with a ohm meter) and another associated with the clutch pedal (this one seems to be working too). Are there others that I have not found? At this time the tractor is dead in the water in the barn. Yesterday I worked on it for about 2-3 hours and could not find the problem. After giving up for several hours I got back on and tried it again and it started right up. I did nothing different and I started and stopped it at least 8-10 more times without incident. After performing several small jobs I went to drive it into the barn and hopped off to open the barn door. As I got up to get off of the tractor the engine stopped (this has never happened before when I get off of it) and would not start after I opened the doors. I again gave up and returned several hours later to find that it would start and I got it into the barn. After getting it back inside I discovered that it again would not start when I tried. Needless to say I am extremely frustrated with this problem and wonder if others have had this problem....and offer possible solutions. Any assistance that anyone can offer would be greatly appreciated!!! Thanks! -Bert

themichelob · Sep 22, 2009

bmckillip--Check the position of your PTO lever. If the PTO is engaged, and you rise off the seat, the engine will stop unless you move the seat forward. Subsequently, you won't be able to restart the engine with the PTO engaged. It's easy to bump that lever getting on and off the tractor without realizing it--especially if you're not using a PTO implement. Good luck and welcome to TBN--
Regards, Mike

Deano · Sep 22, 2009

AI agree with themichelob. Once in a while my PTO will need a "nudge".

Deano

NH-Rob · Sep 22, 2009

how about the forward and reverse pedal. if the switch there is sticking it should shut off the tractor when you get off the seat. try working the pedal back and forth and then try starting it.
Rob

ByronBob · Sep 22, 2009

As others have said you have a safety switch issue and it's common in the sense that many people have grumbled with these issues before. Any one of the switches will cause the tractor not to start and it's for your (well) safety.....

Anyway. Seat switches, pto, rocker pedal and transmission switches are on the tractor. Any of them if not in neutral will cause the unit not to start. As you are learning it's so close to in or out that the tractor starts occasionally. If I were you I'd try to eliminate switches to see which one is the cuprit.

Locate the switches and clean them, blow them out / off with air. Then jump for example the seat switch to eliminate it from the circuit. Then move all the levers in an out before you start. With some time and patience you should be able to have an educated guess at which one is the culprit.

It's still an awesome unit. Don't forget that in the frustration of the moment.

ptrotter · Sep 22, 2009

I recently had a similar issue with my B7800 and the issue turned out to be the HST safety switch. Due to its design, it is possible for this switch to be open regardless of the position of the HST pedal so you can't necessarily move the pedal to make it work. This switch is located on the right side, behind the forward edge of the rear wheel, just inside of the HST pedal damper and is very hard to see and get at. The plunger is located inside a little tube and if the tube gets clogged with dirt, the plunger will stick and will not press in the switch, regardless of the pedal position. My dealer recommended spraying the tube and plunger with WD40 and blowing it out with air. After doing this, I was able to start the tractor. I expect you are seeing the same problem. It is very hard to find, but if you look carefully, you will find it.

Paul

kthompson · Sep 22, 2009

It was the PTO safety switch on mine. For what it is worth, in my case the a slight push on the lever and it works fine. I left it that way as an anti theft switch. It might slow them down enough they move on.

crbr · Sep 22, 2009

One suggestion as offered up here in other posts is to rock the hydrastatic pedal and let it find it's neutral position.

My additional $0.02 is that this is an inherent problem that Kubota seems to ignore. If necessary, use your hand to rock the pedal while turning the switch and clutching. May take a little movement, may take a lot and it may take a few tries. This can be an easy fix or a tempermental fix. Be patient. Been there. The (ex) dealer in Maryville, TN says I am crazy.

bmckillip said:
Hello all- I have owned this tractor for about a year now (no problems whatsoever until now). Recently,the past several times that I have used the machine I have experienced some difficulty starting it. Lately when trying to start it nothing happens when the key is turned to the start position. I have narrowed the problem (I think) to a safety switch problem as the starter and battery are both working fine (this machine has only has 140 hrs. on it). I have located two safety switches on the seat and both appear to be working OK (tested with a ohm meter) and another associated with the clutch pedal (this one seems to be working too). Are there others that I have not found? At this time the tractor is dead in the water in the barn. Yesterday I worked on it for about 2-3 hours and could not find the problem. After giving up for several hours I got back on and tried it again and it started right up. I did nothing different and I started and stopped it at least 8-10 more times without incident. After performing several small jobs I went to drive it into the barn and hopped off to open the barn door. As I got up to get off of the tractor the engine stopped (this has never happened before when I get off of it) and would not start after I opened the doors. I again gave up and returned several hours later to find that it would start and I got it into the barn. After getting it back inside I discovered that it again would not start when I tried. Needless to say I am extremely frustrated with this problem and wonder if others have had this problem....and offer possible solutions. Any assistance that anyone can offer would be greatly appreciated!!! Thanks! -Bert

chiggerbait · Sep 23, 2009

Hello bmckillip.
I had the same problem with my Kubota B2320 and was able to correct it. Turns out there is a forward/reverse switch (under the deck) with a pin sticking out of the front. The switch makes contact with a rod coming off of the forward/reverse pedal assembly. I'm not sure how it happened but my switch got out of alignment. I realigned the switch and the problem went away.
The hard part was breaking my fingers so I could get to the switch.
Good luck.

JOHNTHOMAS · Sep 23, 2009

I had a B7800 for 3 years and had the same problem. Did the seat switch and all the levers. Finally concluded it was the HST pedal and found out the B7800 is notorious for this problem. Rock the foot switch till centered for sure then try to start.