JD 770 No Start/Power

[spring1802]

I am having the same problem and it seems to happen atleast once a season .JD 4200 tractor.Last yr. after checking ,measuring ,replacing parts as posted solutions I let the dealer have it.I was told battery has to be at 13.5+ to start so Then it was bad battery. Last month after sitting a couple weeks, charging one yr. old battery still no crank. So I jumped it with truck started and run.I let it sit for a couple weeks ,no crank and will not jump. Took battery to shop ,good.starter rebuilt last year,

 

[jenkinsph]

I think your dealer is mistaken, a common wet cell battery fully charged is about 2.1 volts/cell or 12.6 volts. Most batteries will read a little higher if you measure them right after charging up but this "overcharge" will dissapate quickly. Maintaining a good cranking voltage while starting the tractor is more important. Charging voltage is usually higher around 14+/- volts to expedite the process.

You might have something that is slowly draining the battery and will help with this if it appears it is the case later in the trouble shooting.

If you wan't to diagnose your tractor starting issues just go through the trouble shooting steps outlined in my first post. Battery voltage at terminals before trying to start, then battery voltage while cranking starter, voltage from battery neg to end of battery cable/ solenoid terminal, battery neg to s terminal on solenoid and last battery neg to starter terminal.
Let me know what you get

 

[Coyote machine]

I am having the same problem and it seems to happen atleast once a season .JD 4200 tractor.Last yr. after checking ,measuring ,replacing parts as posted solutions I let the dealer have it.I was told battery has to be at 13.5+ to start so Then it was bad battery. Last month after sitting a couple weeks, charging one yr. old battery still no crank. So I jumped it with truck started and run.I let it sit for a couple weeks ,no crank and will not jump. Took battery to shop ,good.starter rebuilt last year,

As stated already, 13.5 volts is more than what is needed to start your tractor. 13.2~14.5 volts is an acceptable range for an alternator to supply back to a battery that has a load on it like headlights, etc.
No battery will hold that amount of voltage when the tractor is off. In order for the charging system to work a certain amount of voltage over the amount being used by the tractor must be returned to the battery or it will go flat and not start the next time due to insufficient voltage present. This is the combined job of the alternator/voltage regulator. Confirming what was said about a draw on your battery by some circuit when the tractor is at rest, especially over several weeks, is a likely culprit and will eventually kill even a good battery. Batteries are not meant to go from full to empty- this can and will greatly shorten their life expectancy. They ARE meant to go from full to about 80% of full charge and then be recharged via the alt/v reg.

 

[spring1802]

As stated already, 13.5 volts is more than what is needed to start your tractor. 13.2~14.5 volts is an acceptable range for an alternator to supply back to a battery that has a load on it like headlights, etc.
No battery will hold that amount of voltage when the tractor is off. In order for the charging system to work a certain amount of voltage over the amount being used by the tractor must be returned to the battery or it will go flat and not start the next time due to insufficient voltage present. This is the combined job of the alternator/voltage regulator. Confirming what was said about a draw on your battery by some circuit when the tractor is at rest, especially over several weeks, is a likely culprit and will eventually kill even a good battery. Batteries are not meant to go from full to empty- this can and will greatly shorten their life expectancy. They ARE meant to go from full to about 80% of full charge and then be recharged via the alt/v reg.

Thanks I get 12v at battery,starter and alternator but no crank,no click at starter.still nothing when jumped directly.I am thinking the starter is the problem.

 

[jenkinsph]

The starter or the start switch may be the problem.

That is why I asked you to measure from the neg batt terminal to the s terminal on the solenoid. If you get 12v at the s terminal while engaging the start switch then the solenoid or starter look suspect. If you aren't getting voltage at the s terminal the start switch is suspect. Before you assume the switch or solenoid is bad you need to verify a few things.

 

[spring1802]

Yes it is 12 v at starter with key on.When I touch cable to starter there is spark and slight click.

 

[Coyote machine]

Yes it is 12 v at starter with key on.When I touch cable to starter there is spark and slight click.

What cable are you touching to the starter (solenoid?). To clarify further, when you say with key on are we talking about on or cranking position?

 

[spring1802]

Positive from battery to starter while cranking,switch and solenoid replaced 2 yrs ago

 

[Coyote machine]

OK, so what about the starter? You replaced both the solenoid and ignition switch 2 years ago, yes? Why both? And what was the starter's status at that time? Good, marginal?
Sounds like you may be where you were 2 years ago. Can you remove the starter and have it checked out by a reliable rebuilt shop?

 

[spring1802]

Yes I contacted the shop today so that is the next step.thanks I will let u know.