shuts off when jumper cables removed

chip6700 · Sep 30, 2013

I have a B2320 that appears to have a dead battery. I can jump it from my car but as soon as i remove the jumper cable it shuts off. i'm guessing there must be some sort of energized circuit that keeps the fuel going to it, but shouldn't the alternator provide enough power for that. will it not keep running with a dead battery.

thanks

k0ua · Sep 30, 2013

The fuel shutoff solenoid would shut the fuel off if the battery was dead and the alternator was not charging either. Do you own a voltmeter? What does the battery read by itself? What does the voltage read with the alternator spinning. Did you check all fuses and ground connections.?

chip6700 · Sep 30, 2013

i checked all the fuses. when i turn the key no lights come on unless hooked up to the car. i have a check volt meter but barely know how to use it. it did appear to show 12 volts across the battery though which seemed strange. it won't run without being hooked to the car with jumpers so i don't see how to test the alternator

foreman Etexas · Sep 30, 2013

Sounds like the alternator.

k0ua · Oct 1, 2013

chip6700 said:
i checked all the fuses. when i turn the key no lights come on unless hooked up to the car. i have a check volt meter but barely know how to use it. it did appear to show 12 volts across the battery though which seemed strange. it won't run without being hooked to the car with jumpers so i don't see how to test the alternator

Is it possible you have a high resistance connection between the battery posts and the battery clamps? and when you use the jumper cables from the car you are clamping them onto the tractors battery clamps. This would explain having 12.6 volts on the battery posts yet when you turn the key to on that voltage has a huge voltage drop because the clamps are corroded.

I need to know more about where you connected the jumper cables.

I would take the voltmeter and start on the battery posts. Measure the voltage, have a second person turn on the key, the lights and attempt to start the tractor, keep measuring the voltage on the posts, if it drops below about 11 volts or so, replace the battery with a charged good one and keep on testing..

If the voltage stays up, move the probes over to the battery clamps. Repeat tests what happens. if the voltage drops... you have found the problem, a bad connection between the posts and the clamps.

If it stays up. move the negative lead to another clean ground connection on the chassis of the tractor. If it falls here you have found the problem the chassis end of the ground cable connection or the ground cable itself is bad. also repeat this test with the positive lead which normally goes to the big starter bolt.. if you get a different reading on one end of the cable than the other, the cable or connection is defective.

report back.

k0ua · Oct 1, 2013

If you do replace the battery and the tractor starts and runs on its own, now take the voltmeter to the battery post's and measure the charging voltage with the RPM running say 2000 or so.. you should read between 13.5 up to about 14.8 max. This will let you know if the alternator is working or now.. of course check the alternator belt tightness, between 3/8 and maybe 1/2 inch deflection in the middle of the span.

Tx Jim · Oct 1, 2013

1st & easiest thing to do is check all 4 battery cable connections for corrosion and tightness. Then check to determine if alternator is charging.

J_J · Oct 1, 2013

Take the cables off the battery and scrape and clean the cable fitting and the post, and the cable ground to the engine.

With ign switch on, turn on the head lights, and hit the starter, if head lights dim, the starter is getting. voltage.

If the fuel solenoid will not come on and the instruments do not work, you have a dead battery of bad connections.

If everything works with a jumper cable, you have verified a dead battery, or bad connection.

Soundguy · Oct 1, 2013

as a test.. i'd use the charged car battery, and put the tractor battery on charge.

then do K0ua's test for charge votlage. Sounds like bad alt so far.. adn dead battery.

even a dead battery can show a weak charge to the high input impeadance of a VOM.. etc.

again.. post back.

even if the bat cables were coroded.. jumping to start it would get the alt going.. and pulling jump cables off would mean the alt should carry the load.

the cable ends tothe tractor are at least clean enough that jump cables start her.. meaning alt should carry her.

so far.. dead bat and dead alt is what i see. bat MAY just need a charge.

post back

chip6700 · Oct 1, 2013

the tractor only has about 100 hours on it. the battery connections are perfectly clean and there appears to be no corrosion anywhere. i had been bushhogging and had finished and was blowing the tractor off over by my shed and when i tried to start it to put it away, it wouldn't start. so maybe that's the answer, the alternator is bad and wasn't charging. as long as it was running i was ok, which would explain why it will jump but not keep running. i guess i find it hard to believe the alternator would go bad so soon.
thanks for all of the good advice, i will try getting a good battery in there and testing the alternator output.

k0ua · Oct 1, 2013

chip6700 said:
the tractor only has about 100 hours on it. the battery connections are perfectly clean and there appears to be no corrosion anywhere. i had been bushhogging and had finished and was blowing the tractor off over by my shed and when i tried to start it to put it away, it wouldn't start. so maybe that's the answer, the alternator is bad and wasn't charging. as long as it was running i was ok, which would explain why it will jump but not keep running. i guess i find it hard to believe the alternator would go bad so soon.
thanks for all of the good advice, i will try getting a good battery in there and testing the alternator output.

Chip please let us know what you find out. Thanks.

James K0UA

chip6700 · Oct 1, 2013

kubota wants $289 for a new dynamo, i'm going to ask if anyone knows a subsitute for it

k0ua · Oct 1, 2013

Do you have a starter/generator shop in your town? they can be rebuilt pretty easily by those types of folks. Also most auto parts sales, have the ability to test alternators. I would find out for sure what is wrong. before I shelled out the cash.

Soundguy · Oct 1, 2013

i'd throw a generic one on. if a 10si delco is too big.. look at a cs 130 or a hitachi.. those are favorites of antique tractor people that need small diameter alts to repalce small bbl gennies etc. where large 10si models won't fit.

Soundguy · Oct 1, 2013

ps.. keep in mind you will liekly hav to mod the wire system a bit. ie.. if that dynamo uses an external rectifier / regulator pack.. you will need to wire PAST that.. etc.

catfishdaddyengineering · Oct 1, 2013

Was the battery still connected when you had the jumper cables connected and then it died when you removed the jumpers? If so, try what someone above suggested using the car's battery. The tractor battery could have an internal short that is causing the tractor to die after you remove the jumpers. Unless there is a short in the system, alternators will keep the tractor running even if you remove the battery connection.

chip6700 · Oct 1, 2013

yes, the battery was connected and all connections look brand new. the guy at the kubota dealer told me to test the output from the two wires on the dynamo and that they should register 40-60 volts AC. i'll probably have to wait until the weekend to work on it though.

catfishdaddyengineering · Oct 1, 2013

Sounds like the battery has an internal short. I had the same thing happen to a co-worker. He left work in his vehicle, stopped to get supper, and his car would not crank. He called me to come jump him off. His car would crank but die after removing jumpers. We jumped him off but disconnected the positive(+) battery cable this time, and it stayed cranked after removing the jumpers. He drove to Autozone and got a new battery. No problems after that.

Good Luck!

RaydaKub · Oct 1, 2013

I could understand why a car would stop with the short and ignition being too much load for the alternator at low rpm. But a tractor with only 100 hours on it sounds like it would be new enough that it would have a fuel shutoff solenoid that would only be energized when you turn the key off. It would normally NOT be energized. Did I miss something???