L3800 not starting

Toybota · Oct 29, 2014

Hello All,

Was hoping you might be able to help me diagnose a problem I'm having. I jumped on my L3800 this weekend and she wouldn't start. When I turn the key I hear a "click" from under the hood (sounds like the same click I hear when I turn the key to the left to warm up the plugs). I've done some surfing on the forum and have tried rocking the HST pedal while starting, to no avail. I know another step is to attempt to jump each of the 5 million safeties the tractor has to see if one of them is the problem. My question is, how does one do this? My seat safety has been giving me problems - the tractor engine will shut off when i get out of the seat, even if i flip the seat forward. My solution has been putting a weight in the seat when I need to step down while keeping the tractor running. I wonder if this one is the source of the current headache, but wasn't sure how to jump it to test it.

Many thanks for the help.

Bluegill · Oct 30, 2014

The tractor should stay running and crank with no weight in the seat (my does at least), but it has to be in neutral and the PTO off. Check the PTO leaver, move it around. That said, you might have a low battery. Try charging it, or jumping with a good battery

Stubbyie · Oct 30, 2014

You've got a raft of different things to try.

I don't think you have a 'safety' interference problem or you probably wouldn't hear the click you describe.

Try a different known good battery. Jumping alone may not be sufficient. Most battery tests administered by parts houses and box stores aren't worth the effort.

Next, come to think of it, first, examine critically all four ends of all your battery cables for corrosion or damage to cable (internal corrosion shown by bulges).

When you get it lit, check the charging voltage being furnished to the original battery. If less than about 13.8-vdc, suspect a bad battery then move to bad charging circuit component. Try same with known good battery.

Then report back and let's see what the Forum can do to assist.

After battery we start moving toward starter solenoid, starter itself, fuel shut-off solenoid, or maybe even the mice in the wiring harness.

Please post back your experiences so we may all learn.

85Hokie · Oct 30, 2014

Stubbyie said:
You've got a raft of different things to try.

I don't think you have a 'safety' interference problem or you probably wouldn't hear the click you describe.

Try a different known good battery. Jumping alone may not be sufficient. Most battery tests administered by parts houses and box stores aren't worth the effort.

Next, come to think of it, first, examine critically all four ends of all your battery cables for corrosion or damage to cable (internal corrosion shown by bulges).

When you get it lit, check the charging voltage being furnished to the original battery. If less than about 13.8-vdc, suspect a bad battery then move to bad charging circuit component. Try same with known good battery.

Then report back and let's see what the Forum can do to assist.

After battery we start moving toward starter solenoid, starter itself, fuel shut-off solenoid, or maybe even the mice in the wiring harness.

Please post back your experiences so we may all learn.

follow stubbyie's advise - he is dead on......only exception - you would not see 13.8 till it starts.....

sitting , will be lucky if he see's 12.65 V on a fully charged bat tree!

apeckham · Oct 30, 2014

I chased a similar problem on my L3800 for two days. After changing batteries, going through starter, checking cables, trouble shooting wiring the problem turned out to be the HST peddle safety switch. Made good enough contact to pass enough current to only momentarily engage the starter solenoid. Had good Voltage but not enough current. Adjusted switch and has been perfect since.

number9 · Oct 30, 2014

Bluegill said:
The tractor should stay running and crank with no weight in the seat (my does at least), but it has to be in neutral and the PTO off. Check the PTO leaver, move it around. That said, you might have a low battery. Try charging it, or jumping with a good battery

Hmm, mine (HST) starts all the time (standing beside it (I know)) in whatever range I left it in, brake on or not.

ibunker · Oct 31, 2014

Check the Operator Presence Control (OPC) switch located off the linkage to the speed control pedal. I had same problem and lubed the switch while moving the pedal from below the tractor. The OPC switch should be depressed while the speed control pedal is in the neutral position and pop out when the pedal is rocked forward or back. If your are getting off your seat and this switch is not being depressed by the speed control pedal, the tractor dies like it should and will not start. The OPC switch has a rubber boot on the end with a button pin, lube the pin good with WD 40 or liquid wrench and get it moving, the area is hard to see so good lighting is a must. Good luck.

Toybota · Oct 31, 2014

All,

First off, thanks very much for the posts. So I swapped out the battery with a battery known to be good, checked the terminals, and hooked up. Same results. I think I have confirmed that the clutch safety and seat safety are working (I get no "click" when turning the key while either of them are not engaged.). I have been trying to find the Operator Presence Control system, but can't find a picture on the internet, and am not sure I"m looking at the right thing. The attached picture is what i assume to be the OPC (the large black horizontal cylinder), but I can't find a button on the end to lube. Or am I totally off base here?

Jim L. · Oct 31, 2014

Toybota, there are three electrical circuits to check on the L3800HST.

Check these with brake on, PTO disengaged, clutch disengaged (pushed in), sitting on seat. And for safety gear in neutral.

Circuit 1 is to the "Key Stop Solenoid" (Fuel solenoid). Hook a test light to one of the two terminals on the fuel solenoid and make sure that voltage 12V is present at both of those terminals. One is pull-in and the other hold.

Circuit 2 is the starter control circuit. It comes from the Key Switch "ST" terminal, 5A fuse, starter relay, PTO switch, HST switch, Clutch switch. This circuit pulls in the starter relay, when the key switch is in START position.

Circuit 3 is the starter. Terminal ST on the starter gets voltage 12V from the starter relay. Terminal B on the starter gets voltage 12V through two 40A fuses in series. Terminal B should have 12V at all times. Terminal ST should have 12V when the key switch is in "START" position.

Please tell us what you find, and we'll take the next step.

ibunker · Oct 31, 2014

The OPC is above that in picture on my tractor, hard to see, look farther back, too. You may see some wires leading up to the switch.

Toybota · Nov 1, 2014

All,

Thanks to everyone who responded. I finally got her running again. It WAS in fact the OPC - it just took me a while to find the darned thing. On my model it's located directly under the ignition key. I pushed it in all the way, turned the key, and voila - she fired right up. It's in a pretty tight location, so I had to remove it to adjust and lubricate it, but after re-installing it the tractor starts every time. And to make things even better, now i don't have to put a weight in the seat to keep it running when I step down - so apparently that problem was caused by the OPC and not the seat safety.

Again, thanks everyone. Much frustration and head scratching has been cured.

apeckham · Nov 2, 2014

Kubota must have had a jig problem on the assembly line with as many of these problems that have been reported.

Glad you got it going!

Spent a couple hours on mine today and noticed I have an oil drip coming from the steering box. Need to get it in the shop so I can get it cleaned up so I can pin point the leak.

roadracer86 · Nov 22, 2014

apeckham said:
Kubota must have had a jig problem on the assembly line with as many of these problems that have been reported.

Glad you got it going!

Spent a couple hours on mine today and noticed I have an oil drip coming from the steering box. Need to get it in the shop so I can get it cleaned up so I can pin point the leak.

I have the same problem; did you get yours fixed? Mine had a cut seal on the steering input shaft which was leaking down to the bottom of the box. Mine is just off warranty and I'm not getting much help from Kubota. If yours is still in warranty get it fixed; those boxes are majorly expensive. Seal kit is $200 for a couple of seals and o-rings; ridiculous.
Ball screw is $900+ and the box is $1200+.

roadracer86 · Nov 22, 2014

Just an FYI, if the oil seal on the ball screw is leaking you're SOL since the unit is non-service item; meaning that you have to purchase the whole ball screw assembly ($900+) which is what I was facing a few weeks ago. $900 bucks for a $4 dollar seal; unbelievable. By the way Kubota superseded the part number 3 times since 2012. Typically supersession indicates updates or improvement in a parts design.

Orange Power · Nov 22, 2018

I was having the same problem on my L3800 HST. Sometimes started with first turn of key. Then refused to restart next time. Just loud click or a bad grinding sound at starter like it wasn't getting enough current. Never knew when it would or wouldn't start and could see no pattern. After reading other posts I decided to check the HST interlock switch which I didn't know it even had. After seeing how that switch is activated I placed a flat blade screwdriver tip between the plunger on the switch and where it contacts the linkage to HST pedal. Well that was all it took. Started every time with no issues. Then I simply removed the one bolt that holds the switch inplace and threaded it 2 turns farther into the bracket and remounted it. This extended the switch plunger enought that when hst is in nuetral position the plunger is pushed farther into the switch to make a good xonnection. 15 min fix ,no cost and no more frustration. Hope this works for you.

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