I just purchased an old yellow deck JD STX38 in near perfect condition. The battery is probably not the best but a few days after charging it is able to start the tractor. When I tested voltage was at 13.6 while running. After about 20 minutes of mowing the battery is completely drained. How many amps should the clutch pull normally?
Thank you, does the manual say where to measure this?
sgkent
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I'd test the charging system and try again. If the charger is putting out 13.6 and the battery is still drained, something is wrong with that, whether it is the charging system, the diodes, connections or battery I can't say. Most lead acid batteries last a max of 4 - 5 years, and less if they are allowed to go flat and sulfate.
StarTech
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The resistance is measured at the PTO clutch. The reason to measure the resistance instead amp draw is most meters can't handle high current unless they are design to.
Also these PTO clutches can be partially shorted and still work. When they do they draw more current than charging system can provide they and drain the battery. I have seen PTO clutches to up to 20 amps and still work. Several years I had one customer to refuse to except his PTO clutch was bad even though it was melting the wiring insulation because it was still working.
Also note the charging system must be working properly in order recharge and provide for current demand. So it needs to be tested too.
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Hi Tooler,
I happen to have one of these among my collection of riders. They have always been a popular model. I've never understood the dispute/preference between the "yellow deck" and the 'black deck models". Maybe it is a color scheme thing.
Disconnect the PTO clutch and measure the Ohms resistance between the 2 harness connector pins of the clutch. Let us know what the reading is.
You checked voltage after the battery just came off the charger, that is called "surface charge" and does not mean the battery is good. The old battery is still questionable. If this set for a long time, don't expect the battery to be any good. These small batteries are not as robust or reliable as a typical vehicle battery.
A meter can read voltage, but it cannot test or verify amperage. Voltage is potential to do work; Amperage is what gets the work done. This is where meters can trick a person. (Gives false hope)
I think your charging system is not working properly and that will cause the PTO clutch to pull down a battery pretty quick. The PTO quitting is a symptom, not a cause.
Get a new battery in this and then check the charging voltage while running at high RPM. It should show higher than battery voltage when tested at the battery. Usually, around 14.2-15V is what I look for.
If the voltage stays a battery voltage, you need to start looking at the charging system.
I will stop here for now.
We can also help you cover that problem as needed.
I happen to have one of these among my collection of riders. They have always been a popular model. I've never understood the dispute/preference between the "yellow deck" and the 'black deck models". Maybe it is a color scheme thing.
Disconnect the PTO clutch and measure the Ohms resistance between the 2 harness connector pins of the clutch. Let us know what the reading is.
You checked voltage after the battery just came off the charger, that is called "surface charge" and does not mean the battery is good. The old battery is still questionable. If this set for a long time, don't expect the battery to be any good. These small batteries are not as robust or reliable as a typical vehicle battery.
A meter can read voltage, but it cannot test or verify amperage. Voltage is potential to do work; Amperage is what gets the work done. This is where meters can trick a person. (Gives false hope)
I think your charging system is not working properly and that will cause the PTO clutch to pull down a battery pretty quick. The PTO quitting is a symptom, not a cause.
Get a new battery in this and then check the charging voltage while running at high RPM. It should show higher than battery voltage when tested at the battery. Usually, around 14.2-15V is what I look for.
If the voltage stays a battery voltage, you need to start looking at the charging system.
I will stop here for now.
We can also help you cover that problem as needed.