Starter issue?

reprosser · Jul 1, 2013

I have a Kubota L3240 - a few years old. Last week, I turned on the switch, the control panel flickered a little, and when I tried to crank - the system died. I turned off the key, turned it back on, and the panel flickered a couple times and died.

After sitting a few minutes, I tried again with no luck.

I have checked all the fuses and relays, changed the battery, tightened connections, but cannot seem to find the problem.

When the system shuts down, the voltage at the switch drops to about 4 volts. Voltage across battery terminals is 12.4 v. If I pull the fuse for the alternator, the voltage rises a couple volts, and if I pull the fuse to TM controller, the voltage rises a couple volts. If I wait for an hour or so, eventually the voltage at the switch will come back up to 12.2 volts, and after re-inserting all the fuses, the panel lights up when the switch is on - but if I try to crank, I hear the starter solenoid engage, and the system shuts down.

I removed the starter, and it seemed to work ok when connected outside of the tractor. I put the starter back on the tractor and manually shorted the solenoid, and the starter tried to turn over the engine, but only turned the fan about 1/2 way around. Voltage dropped back to around 4 volts.

I plan to replace the starter today, but if this does not fix it - I have no clue what to do next. I will have to get the dealer to come by, load it up and troubleshoot in the shop. Unfortunately, it is inside the tractor shed with the bush hog connected. Going to be a chore to get it out and on a trailer...

Any ideas for something else to check?

KennyV · Jul 1, 2013

Replacing the starter will have No effect...
You are dropping voltage somewhere... It 'could' be in the battery itself, or at any one of Many connections Including several grounding spots.
You can find this with a volt meter... You will have to have a fair Load on the system, All the lighting "may" be enough load to allow you to do a voltage drop test... KennyV

reprosser · Jul 1, 2013

OK. I guess it is just the load from switching on the starter that is making the problem more evident? Will spend more time with the volt meter...

David_Kb7uns · Jul 1, 2013

Double check both battery connectors, starter connector and go check both ground bolts for battery cable and engine ground make sure clean and tight bolts.. Also you may have battery tested to see if it has bad cells.

David Kb7uns

Deano · Jul 1, 2013

Battery voltage low...see chart View attachment voltchart1.bmp

reprosser · Jul 1, 2013

I did replace the old battery with a new one as the first response. Had the same behavior as before.
Since I have been troubleshooting for 2 days, I probably need to recharge.

The fact that the voltage seems to creep back up makes it more challenging as well - as I am testing, not sure if something I did impacted the rise, or if it occurred on its own.

When replacing a fuse, I have seen the voltage drop, and then rise higher than before the fuse was removed.

Kubota 2007 · Jul 1, 2013

Sounds like a shorted out battery, it will show normal voltage until it is loaded up. Shorted out battery's are the biggest cause for replacing good starters. Shorted out battery's can't be jump started with a know good battery, only replaced.

ibnxe · Jul 2, 2013

From your symptoms I would say you have a bad connection somewhere. The battery connections need to be both clean and tight. Lead terminals oxidize in air... if the terminals are gray they need to be cleaned before tightening. Check the ground side of the circuit by checking for voltage drop between the negative battery terminal of the battery and the engine block. Do the same between the positive battery terminal and the starter. You could have a bad ignition switch. check that you are not loosing voltage there.
With a little probing, you should be able to find the fault.

Kubota 2007 · Jul 2, 2013

I didn't see that you replaced battery, Guess I skipped that post.

reprosser said:
I did replace the old battery with a new one as the first response. Had the same behavior as before.
Since I have been troubleshooting for 2 days, I probably need to recharge.

The fact that the voltage seems to creep back up makes it more challenging as well - as I am testing, not sure if something I did impacted the rise, or if it occurred on its own.

When replacing a fuse, I have seen the voltage drop, and then rise higher than before the fuse was removed.

reprosser · Jul 2, 2013

I will have the battery tested, and then start again on tracking down the voltage drop. I agree it seems to be a connection issue.

I will start by cleaning the <good> battery connections, connecting the batter terminals, and removing the fuses to start checking voltage. Since the battery GND is connected to the frame, and the starter is connected to the engine, I will check for stray voltage between frame and engine block.

Once I get good voltage to the starter, I want to see if I can manually turn over the engine. If I only have the starter connected, it should be able to turn over the engine - even if nothing else is connected? I know it won't start since the Key Stop relay will not be engaged. This should eliminate the starter, and the GND connection if it works.

Thanks for all the help and suggestions.

repete · Jul 2, 2013

With everything off, disconnect the negative battery terminal and put a light bulb between the cable and the battery terminal. If it lights up then you are draining the battery when sitting. If there is no light to the bulb, place a volt meter between the negative cable (red lead) and the battery post (black lead). No voltage on the meter is good. If you have voltage, but no light, change the meter to the highest amp scale then work your way down to see the milliamp scale. That will tell you how much current drain is on the system.

KennyV · Jul 2, 2013

reprosser said:
....I know it won't start since the Key Stop relay will not be engaged. ...

...

If you do as stated, it Will start. The key Stop relay momentarily pulses the fuel shut off. Tou do not need power anywhere except to the starter for Starting the engine... Without power to the key switch, You will have to manually pull the fuel shut off.

reprosser · Jul 4, 2013

Thanks KennyV - did not know that.:thumbsup:

OK - I have started from scratch with nothing connected, checked voltages, and connected one item at a time. At each point, I checked voltage, and manually turned over the starter by shorting the solenoid. I have installed fuses one at a time and validated that the voltage is steady. I have everything connected, all fuses, and I can start the tractor with the manual starter method. I am at the point where I have been before - everything seems OK, but if I turned the key to crank, it crashed. Before I try to crank with the key, I want to verify the starter-key system. I had to stop for tonight, but will continue tomorrow.

Since the main thing (only thing?) that happens when I turn the key to position 2 for cranking - is to provide power to the starter relay, I am investigating the relay. One thing I noticed with the relay removed from the plug is that there is 12v across the "coil" wires on the plug when the key is "on" (position 1). I did not expect to see 12v at the coil until the key is switched to crank (position 2).

Should there be 12v on the starter relay when the key switch is in position 1 (on, but not cranking) ?

There is also a diode assembly - I think it is called a flyback diode. I have no experience with this, but a little googling makes me think that even if the diode is shorted or open, it should not cause 12v on the coil.

I will be checking the key switch tomorrow - but I am pretty sure I originally checked for 12v on the position 2 tab, and it was OK.

reprosser · Jul 5, 2013

Tried the starter and it works fine. The culprit turned out to be a bad connection on the batter ground cable. Looked OK, and was tight, but when dis-assembled there was some rust. After cleaning and reassembly, the voltage stayed @ 12v during operation.

Thanks all!

Xfaxman · Jul 5, 2013

For future reference: Starter Voltage Drop - YouTube

reprosser · Jul 5, 2013

Good video - wish I had seen it before...

Deano · Jul 6, 2013

Xfaxman said:
For future reference: Starter Voltage Drop - YouTube

Great video!! Now, will I be able to find it when I need it??!! No!!:laughing:

gwdixon · Jul 6, 2013

reprosser said:
Tried the starter and it works fine. The culprit turned out to be a bad connection on the batter ground cable. Looked OK, and was tight, but when dis-assembled there was some rust. After cleaning and reassembly, the voltage stayed @ 12v during operation.

Thanks all!

This is a common problem and has many threads about it. I usually post but somehow missed this thread.

The best permanent fix is to route the battery ground to a bolt on the engine. A longer cable may have to be used to reach.

While at the auto parts store buying the longer cable it is wise to pick up a spray can of that red goop for stopping corrosion on battery cables.