Kubota not firing - 1985 L305

[dcrowder]

Engine troubles with an 1985 Kubota L305 tractor. I made a video showing how things are working in hopes it helps to diagnose the problem. The video can be found here, https://youtu.be/JAF9IWwyCZM

Things that I have done leading up to this point are:

1. Replace the coolant pump which was tested by successfully starting the tractor without any leaks.
2. Install some new led lights which led me to discover that the
3. voltage regulator was in need of replacing (replaced)
4. Remove the starter and clean off the copper terminals to ensure the starter solenoid was working which it is. The radiator fan and alternator spins when attempting to start the engine.
5. Bleed the fuel line below as well as the leads to the fuel injectors
6. Tested the first of three glow plugs and it works to my knowledge (voltage drops to 7.5-7.9)
7. Engaged the starter while the glow plug was removed and I was able to hear air being forced out.

As described in the video, the engine is not firing when engaging the starter. Its been between 80-90 degrees outside and im not sure if the glow plugs would really be needed to get this thing working, but even when I tried starting the tractor before this issue and the glow plugs werent warmed, the tractor would at least attempt to fire which isnt the case now.

So I am at a point now where I am totally stumped and do not know where to turn now. Any information would be greatly appreciated to get this old champ working once again. Thanks!! - Dan

 

[D2Cat]

Welcome. Noticed in your video you're engine will never start until it turns over much faster then you demonstrated.

I'd suggest having your battery tested at a reputable shop. Then clean all ground connections by remove wire and cleaning metal on wire and frame before reinstalling. Also, check under wire insulation for oxidation. Many time battery wires may look good, but are deteriorated under the insulation. Any oxidation and I'd suggest replacing the entire wire.

Once your engine turns over faster, it may start, or you may need to address fuel issues.

One step at a time. Don't change out to many items or you may have more difficulty isolating any problems.

 

[85Hokie]

Dan,

looking at the video .....D2Cat is on the money - that ol girl has got to spin faster than that to start.

When you bled the lines.....you got no bubbles?

After you check all the wires again like Cat said - get some help on that battery, It needs to be 100% fully charged, the compression (assuming it is good) cannot build fast enough to ignite the mixture.

When did it run last?

Has it always been slow to turn over?

Help us out some more with the past history.

 

[dcrowder]

I suspected that the starter was a bit weak. Would there be anything that would prevent the starter from turning the fly wheels as fast as they should be if the starter is getting the juice that it needs?

In the meantime I will go through the wires to check their integrity and as well as the grounds.

Thanks, I will keep you posted on what I have done and their results.

 

[dcrowder]

85Hokie,

There were no bubbles in the fuel line.

As far as the battery goes, I have been having issues with the battery for months in terms of not being charged and having to jump it with the SUV. I topped it off with distilled water and I finally purchased a charger and recharged the battery and it seemed to be ok in terms of reading 12+ volts. But im not sure if that means it's in prime condition.

I have been using my SUV's battery which is much newer than the tractor (Jan 2016), and this is what I used to get it started 2 weeks ago after I replaced the water pump. This is the same battery that I tried using this weekend to get it going and its still slowly turning.

Since purchasing the tractor last year it has slightly degraded in terms of how quickly it fired up, but never like it is now.

The other that I suspect is that the alternator isn't charging the the battery, but I haven't gone down that road of testing just yet. The skinny red wire (12 guage I think) coming from the alternator is crap and needs replacing. Im not sure where it leads to just yet, but I can find out in the A.M.

 

[North Idaho Wolfman]

First thing I noticed is you have the battery hooked to a small set of jumper cables then those are hooked to the battery cables, that's not going to get it to turn.

Big jumper cables or hook battery directly to the cables.
Make sure your using is a battery of the proper size.
Take the battery to a automotive store and have it load tested, even a battery that seams to charge can be dead!

 

[Tooljunkie]

My L1501 always started poorly, cranked slow. NEW battery solved the issue.
Boosting a weak or failing battery is a waste of effort. Not only is it hard on starter, generator and wiring its horribly frustrating. A weak battery Will burn out a perfectly good starter.

Boosting a bad battery is an explosion waiting to happen.

Good,fully charged battery (like new condition) will test at 13.2 volts. I do not trust the digital load testers, i use a carbon pile tester that puts an actual load on battery.

 

[rbargeron]

Video shows not enough electric power getting to the starting system. It needs to spin over faster. Best way to assist the starting system is to use good jumper cables connected to another running vehicle (like your SUV). The running voltage is up closer to 14v. Even with the glowplugs turned on, the voltage should stay up closer to 12v or higher. With good cranking voltage it will spin faster and should start right up.

On a L305 the glow plugs run whenever the starter is running. If you run them first it will definitely start quicker, but it should start eventually anyway on warm days. It needs big wire with good connections to get enough amperage. Good luck - let us know when you prevail !

 

[dcrowder]

Video shows not enough electric power getting to the starting system. It needs to spin over faster. Best way to assist the starting system is to use good jumper cables connected to another running vehicle (like your SUV). The running voltage is up closer to 14v. Even with the glowplugs turned on, the voltage should stay up closer to 12v or higher. With good cranking voltage it will spin faster and should start right up.

On a L305 the glow plugs run whenever the starter is running. If you run them first it will definitely start quicker, but it should start eventually anyway on warm days. It needs big wire with good connections to get enough amperage. Good luck - let us know when you prevail !

One thing that I noticed was that the wires on the battery are different. The positive wire is maybe a 1 gauge and the negative a 2 gauge. So I bought two new 2 gauge battery wires and a terminal cleaner to see if that will have an affect on things. I also had the battery tested at AutoZone and they said it's good. The reading was 12.8 volts.

 

[dcrowder]

I had the test done on the Battery and it came up 12.8. Do you think that I could possibly need a stronger battery?

 

[dcrowder]

Success!! She's running once again!

So I replaced both battery cables/wires with matching 2 gauge wires and cleaned off the battery terminals and she fired right up. I would have never considered that prior to talking to you great fellas and gals (if applicable).

I will continue going through and inspecting the rest of the wires to ensure they are all in good standing, but for now all is well.

And who says Mondays suck!?

 

[Russell King]

Don't know if the L305 has a decompression knob or not but noticed you did not use one. If it has one use it to spin up the engine speed the apply compression (release knob) to start.

Glad you got it going!

Sent from my iPad using Tapatalk

 

[rbargeron]

It's surprising how many engines won't start because the system has corroded wires or terminals or harness plugs somewhere.

Every wiring connection starts life shiny new. But when they pass current, corrosion starts (on a molecular scale). Eventually there's enough damage to affect function. The performance margin it had when new is gone. Luckily cleaning it all up restores it to health. Glad you fixed it. Take care, Dick B

 

[dcrowder]

Not sure where my last update post went, but I got it working!

Changed out the battery cables with matching 2 gauge cables and cleaned off the battery terminals and it fired right up.

I really just want to say thanks everyone for the help....felt a bit defeated but you got me through.

 

[Tooljunkie]

Glad you got it solved.
The micro-arcing is called fretting if i recall correctly. Once it begins to corrode it just continues until it gets attention. It can be frustrating. Been there done that way too many times.