Kubota L35 Hard Starting When Cold

Russell King

Well-known member
Lifetime Member

Equipment
L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
7,606
2,927
113
Austin, Texas


That 1.0 ohm is what they should be reading? Apologies but I can't find the proper ohm reading for glow plugs in my shop manual. I removed the glow plug rail to check resistance on the plugs... all read individually 1.6 ohms. My multimeter does fluctuate a tiny bit, but generally they seemed to sit at 1.6.

Possible stuck injector on one cylinder?
1.0 is a value that has been stated by others on this web site. The WSM I have for L175 to L345 states 1.5 Ohms for an individual glow plug.

IMG_0663.jpeg
 
  • Like
Reactions: 2 users

whitetiger

Moderator
Staff member

Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
Nov 20, 2011
3,545
1,975
113
Kansas City, KS
Here are a couple of the WSM pages for the glow function.

Screenshot (117).png Screenshot (119).png
 
  • Like
Reactions: 2 users

LeanGreenMan

Member

Equipment
L35
Apr 30, 2026
31
8
8
Colorado
Thank you all so much. I think this is a glow plug issue.

Secondly, I apologize. The WSM I have is a print out that was stuck in a binder with a bunch of pages out of order (that's how it was shipped to me). I sat down today and properly reorganized it. I had been struggling to find detailed troubleshooting because I had been looking in the 9-M section, not the 9-S section.

In the 9-S section, and in the copies white tiger so kindly included, it shows the glow plugs are supposed to read, factory spec, 0.5 ohms. Mine are reading 1.6 ohms. That leads me to think the glow plugs are burned out.

Now, I am going to do a little more double checking before I order glow plugs, but I expect that is either the main issue, or a big part of it. There may be a secondary issue, more on that below.

Thirdly, I apologize again. My only experience with a diesel has been my '91 F250 with the 7.3 IDI. That was a massive learning experience, and frankly a huge part of what gave me the confidence to buy an old diesel Kubota. With my IDI, the glow plug "Wait to Start" light runs for about 15 seconds on a cold engine, the light goes off, and I am good to start the engine (down to about 0*F). Yes, it took me a lot of work to get that old IDI to that point.

The thing is on that IDI, I believe those are traditional glow plugs. While the WTS light goes out, the glow plugs are in fact still energized for a few more seconds, and then will cycle for a few seconds after that. This is I believe a system to reduce emissions per the EPA or California or something. It has the secondary benefit of leaving glow plugs that are still burning hot while the engine is cranked over.

At any rate, the L35 has what are called a "Super Glow Plug". Per the WSM, the glow plugs should have a 5 second or less warming time for any temperature in which I will attempt to start this tractor. That is, 5 seconds, at -15*C, and what I believe is called an inverse bell curve for time with increasing temperature. This leads me to believe the glow plug controller, and the coolant temperature sensor is in fact working correctly.

I say all this as it appears these "Super Glow Plugs" may stay hot after the relay clicks off and the glow plug light goes out. They do not need to stay energized while the engine starts, as they stay hot. That said, this is what I reference as a potential secondary issue above. My secondary issue concern is in the WSM, on page 9-M9 "Function, Step 3", it seems to suggest that the glow plugs are reenergized when the key is turned to "Start". It is possible that my struggle to start when cold is possibly due to the glow plugs not being reenergized when the key is turned to "Start". This is something I can check tomorrow. I'll pull the L35 in the garage, let it cool, pull all the covers off, and read voltage as the glow plug bus bar while the engine is being turned over.

I do have an issue, where the key no longer shuts the engine off. This may be a failure of the engine shutoff solenoid, wiring issue, or ignition switch issue - I haven't had time to diagnose this yet. If it is an ignition switch issue, it is possible that the potentially faulty ignition switch is also causing what may be the secondary issue described above.
 

Hugo Habicht

Well-known member
Lifetime Member

Equipment
G1900
Jun 24, 2024
1,511
2,161
113
Ireland
The resistance you are measuring could be your multimeter wires, see my post above.

But I do not see any glow time specification or test in the manual pages above. Or have I missed them? The 3s mentioned look very short to me.
 
Last edited:
  • Like
Reactions: 1 user

Nicksacco

Well-known member

Equipment
Kubota L35 TLB, 2014 RTV-1140CPX
Sep 15, 2021
764
502
93
Bahama, NC
Be very careful taking out the glow plugs. If corroded, they easily snap right off.
Yep - it happened to me.

I hope that is the starting problem - a relatively easy fix,

@Russell King mentioned in the startup video you did, that it looks like maybe a cylinder is late to the party.
It appears that way to me too.

If your emerg stop works, pull the stop and crank the engine over for 3-5 seconds 2-3 times, then put the emerg stop back off and try and start. That might warm the engine enough to start... might be a good test.
 
Last edited:
  • Like
Reactions: 1 users

LeanGreenMan

Member

Equipment
L35
Apr 30, 2026
31
8
8
Colorado
The resistance you are measuring could be your multimeter wires, see my post above.

But I do not see any glow time specification or test in the manual pages above. Or have I missed them? The 3s mentioned look very short to me.
Page 9-S11 that white tiger posted above, top of the page, in the box. If I am misunderstanding, please feel free to correct me.

My 7.3 IDI likes glow plugs that are 0.3-0.5 ohms, as far as I can tell my multimeter seems to be able to reliably read that. To be clear it doesn't "sit" at say 0.4, it will bounce up and down a little bit.

I have attached the page from my WSM for the super glow plug, and timing of the warming cycle (graph at bottom).
 

Attachments

LeanGreenMan

Member

Equipment
L35
Apr 30, 2026
31
8
8
Colorado
Be very careful taking out the glow plugs. If corroded, they easily snap right off.
Yep - it happened to me.

I hope that is the starting problem - a relatively easy fix,

@Russell King mentioned in the startup video you did, that it looks like maybe a cylinder is late to the party.
It appears that way to me too.

If your emerg stop works, pull the stop and crank the engine over for 3-5 seconds 2-3 times, then put the emerg stop back off and try and start. That might warm the engine enough to start... might be a good test.
Thank you for the advice.

Based on what has been said before, I assume the cylinder being late to the party is an injector issue?
 

PoTreeBoy

Well-known member
Lifetime Member

Equipment
L35 Ford 3930
Mar 24, 2020
3,740
2,309
113
WestTn/NoMs
The resistance you are measuring could be your multimeter wires, see my post above.

But I do not see any glow time specification or test in the manual pages above. Or have I missed them? The 3s mentioned look very short to me.
Here's the curve, bottom, that @LeanGreenMan referenced. Only one point is labeled. The real test would be a DC ammeter directly to the glow plugs.
1000007216.png
 

PoTreeBoy

Well-known member
Lifetime Member

Equipment
L35 Ford 3930
Mar 24, 2020
3,740
2,309
113
WestTn/NoMs
For anyone who is curious, this is what I am referring to with the "secondary issue" above.
I thought your secondary issue was fuel shutoff! The only time I had to use the emergency knob, the small c-clip that holds the solenoid rod to the shutoff lever had come off, allowing the rod to disconnect.

BTW, the glow plugs are also powered through the ignition switch when it's in the 'start' position.

As a point of reference, Katy started fine, maybe a little more reluctantly, when her timer was out of commission. But it was summer time in Ms, not 35F. Depending on where you are, the altitude could be making it more difficult too. Come to think of it, my plugs were working during start so I did get a little heat boost. If yours are shot you're not getting even that.
 

LeanGreenMan

Member

Equipment
L35
Apr 30, 2026
31
8
8
Colorado
I thought your secondary issue was fuel shutoff! The only time I had to use the emergency knob, the small c-clip that holds the solenoid rod to the shutoff lever had come off, allowing the rod to disconnect.

BTW, the glow plugs are also powered through the ignition switch when it's in the 'start' position.

As a point of reference, Katy started fine, maybe a little more reluctantly, when her timer was out of commission. But it was summer time in Ms, not 35F. Depending on where you are, the altitude could be making it more difficult too. Come to think of it, my plugs were working during start so I did get a little heat boost. If yours are shot you're not getting even that.
No, secondary issue I was referring to above is the glow plugs possibly not reigniting while the engine is cranking. I just refer to the fuel shutoff issue as a potential ignition switch issue that may cause the glow plugs to not reheat. Of course that is all moot if the glow plugs aren't working at all.

I'm at 9500ft in Colorado.

I haven't had time to diagnose the shutoff issue, and as the emergency knob does shut it off, that's what I've been using meanwhile.


Does anyone know if there is a removal tool for stuck glow plugs for the L35 such as this one for the 7.3 and 6.5?

 
  • Like
Reactions: 1 user

LeanGreenMan

Member

Equipment
L35
Apr 30, 2026
31
8
8
Colorado
Update:

New glow plugs showed up, ordered them from Messicks. They read roughly 1.6 ohms, just like the old ones, and unlike the 0.5 spec'd in the manual. I replaced them anyways - that was time consuming as the old ones were very swollen. No change to cold starting.

Cleaned battery terminals and battery ground to frame. Battery still reads 12.6 volts after quite a few starting attempts. No change to cold starting.

Checked voltage to glow plugs again. 10 volts while they are warming, 8 volts when cranking. Not sure if that sounds like an issue to anyone? I can understand a voltage drop when cranking, but I would think they should be getting 12+ volts when warming and maybe 10 volts when cranking. Anyone have input on that?

Currently reading up on the valve adjustment. Never done anything like that before so I'm rather determined to not screw something up.
 

Hugo Habicht

Well-known member
Lifetime Member

Equipment
G1900
Jun 24, 2024
1,511
2,161
113
Ireland
I'd say the voltages you measured are correct. 0.5 Ohm / 3 = 0.16 Ohm which means with 12V there are 72 Amps flowing. Depending on the condition of the battery 10V are not unusual. Keep in mind voltage is lost over wires and contacs too.

When cranking the battery voltage can drop to 3V in very cold conditions. Again, 8V is nothing unusual.

Have you tried a newer, bigger battery? Maybe your battery is simply on the way out.
 

LeanGreenMan

Member

Equipment
L35
Apr 30, 2026
31
8
8
Colorado
I'd say the voltages you measured are correct. 0.5 Ohm / 3 = 0.16 Ohm which means with 12V there are 72 Amps flowing. Depending on the condition of the battery 10V are not unusual. Keep in mind voltage is lost over wires and contacs too.

When cranking the battery voltage can drop to 3V in very cold conditions. Again, 8V is nothing unusual.

Have you tried a newer, bigger battery? Maybe your battery is simply on the way out.
I may be misunderstanding completely, I probably am. I do want to clarify that each individual plug measures 1.6 ohms.


I had the battery load tested at Oreillys and it came back "good".
 
Last edited:

PoTreeBoy

Well-known member
Lifetime Member

Equipment
L35 Ford 3930
Mar 24, 2020
3,740
2,309
113
WestTn/NoMs
I may be misunderstanding completely, I probably am. I do want to clarify that each individual plug measures 1.6 ohms.


I had the battery load tested at Oreillys and it came back "good".
Off the top of my head, those voltages sound a little low to me. The important thing, does it spin over or sound like it's struggling? Maybe you could record it cranking and post on youtube with a link?
 

LeanGreenMan

Member

Equipment
L35
Apr 30, 2026
31
8
8
Colorado
Off the top of my head, those voltages sound a little low to me. The important thing, does it spin over or sound like it's struggling? Maybe you could record it cranking and post on youtube with a link?
I agree that the voltages seem on the low side and I also agree that it sounds like it cranks slow. Will reinstall the battery and upload a video ASAP. Maybe I'm wrong. Still need to check the valve clearance.
 

#40Fan

Well-known member
Jul 21, 2022
545
381
63
USA
Watching your video, when cranking, you can hear it speed up for a small amount of time.

rrr rrr rrr REE rrr rrr rrr REE......that kind of noise. The REE is the low compression cylinder.
 
  • Like
Reactions: 1 user