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JOhn Deere 425 won't even crank

Posted by pugmark 7b NC (My Page) on
Sun, Nov 14, 10 at 15:43

HI,
My JD 425 was running perfectly. Today it wouldn't start,but had starter clicking noise. Charged battery although it was 75% charged, and it started and ran fine. I shut it off, and now it won't even click. Battery is fully charged, but all I hear when I turn the key is slight hum which sounds like it's coming from the fuse panel. The starter does not click or even try to spin. There is a green LCD light on the panel where the fuses are, and it lights up when key is turned. The time dely thing was rep[laced about a year ago. This is an older model 425 and it has a Kawasaki engine.
Any suggestions greatly appreciated


Follow-Up Postings:

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RE: JOhn Deere 425 won't even crank

#1 Make sure the battery is fully charged and GOOD. Make sure the battery cables are clean and corrosion free and snug AT BOTH ENDS. Check the starter bolts and make sure they're tight. A VM showing 12 volts does not mean that the battery is good and neither does any meter on any battery charger. A VM across a static battery should show 12.7 VDC or higher to about 13.2 VDC.

#2 Make sure the charging system is operating properly. To do that you need a KNOWN GOOD battery. Simple test... with a known good battery start the tractor and let it idle. Turn on the lights. As you raise the RPM to WOT the lights should get brighter and a VM across the battery should show 14 VDC or slightly higher..

#3 That slight hum you hear from the panel is most likely a relay telling you that your battery is not good or it could be a bad relay.

#4 If you keep trying to start your 425 with a bad battery you will be buying a starter and you won't like that.


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RE: JOhn Deere 425 won't even crank

Well as usual, the answer I received here was accurate! I took the battery in and had it checked. It was fine, so I cleaned the terminals and battery posts and tried again. Tractor started right up! Thanks so much for your detailed instructions!


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RE: JOhn Deere 425 won't even crank

You're welcome.


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RE: JOhn Deere 425 won't even crank

What is the chance that the ignition timer is replaced (which fixes a no spark condition), and three starts later the battery develops a condition that prevents the engine from even cranking? Apparently very good. Thanks for the reco to go to the battery first.


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RE: JOhn Deere 425 won't even crank

Well, if you subjected that battery to some serious, but unproductive, cranking cycles while studying hard to find the cause of a no spark condition................I would say "better chance than winning the lotto".


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RE: JOhn Deere 425 won't even crank

When all else fails, and you suspect a bad battery, try jump starting using your car. MAKE SURE THAT BOTH SYSTEMS ARE THE SAME VOLTAGE.


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RE: JOhn Deere 425 won't even crank

"When all else fails, and you suspect a bad battery," take the battery to someone who will load test the battery right in front of you. Then you'll know if the battery is good or bad instead of guessing.


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RE: JOhn Deere 425 won't even crank

I have been following the advise on this problem (always looking to learn something) and would like to know how trying to start a tractor with a bad battery could ruin a starter, as stated by justalunker on Nov 14, 2010?


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RE: JOhn Deere 425 won't even crank

Because a "bad" battery has very little amp capacity.
This will result in a very pronounced voltage drop when the battery is subjected to its normal (for the application) starter load.
A low voltage scenario coupled with high amp draw will result in sky rocketing heat build up in the starter windings and heavy arcing to the brushes and copper commutator bars of the starter armature. All of which can kill a starter, especially the heating of the wire windings, which will then short circuit into each other once the thin shellac coating of the wires cooks off.


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RE: JOhn Deere 425 won't even crank

Thank you gentlemen. Monie, I am still missing one thing. As you said, " a bad battery has low amp capacity", where then does the "HIGH" amps originate? The starter receives only what the battery delivers. Therefore, if the battery only has potential for low amps where do the high amps come from? please adjust my understanding. Again, thanks for the help.....paulpep


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RE: JOhn Deere 425 won't even crank

Thank you, Gentlemen. Monie, I am still messing one thing. You said that, "a bad battery has low amp capacity". Where, then, does the HIGH amps originate? The starter receives only what the battery delivers, I assume. Therefore, if the battery has potential for LOW amps. Where do the high amps come from? Again, I thank everyone for sharing their wisdom with me......paulpep


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RE: JOhn Deere 425 won't even crank

A GOOD battery has the capacity to deliver SUFFICIENT (high) amps to crank the starter.
As it ages, that capacity diminished to the point it is INSUFFICIENT (low) to crank the engine.

8 penlight batteries will deliver 12 volts, but is insufficient to crank your engine.


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RE: JOhn Deere 425 won't even crank

Well, you had to ask.
To fully grasp the concept, one needs to have an understanding of basic electrical principles.
Typically, the water hose analogy is used to demonstrate the basic principles.
The supply water plumbing of a house is thought of as a battery. The hydrant valve would be a switch. The garden hose would be the conductor (battery cables) carrying water (current) to a sprinkler head (starter).
The standing water pressure of the house plumbing (in PSI) is analogous to "battery power" (measured as voltage).
In this comparison, opening the hydrant valve allows water to flow through the hose to the sprinkler, causing it to spin.
In an automotive setting, operating the solenoid allows electrical current to flow through the battery cables to the starter, causing it to spin.
Various factors affect the performance of an electrical circuit much the same as variables in plumbing will affect the spinning sprinkler.
If you reduce the PSI of the house water supply, you expect the sprinkler to spin more slowly, similarly a reduction of battery voltage will result in a slower spinning starter.
If you change from a 3/4" diameter hose to a 3/8" diameter hose, the sprinkler will spin slower. If you change from the OEM battery cable size to some wires half their size, the battery will spin slower.
If you change the sprinkler out for one that is hard to turn, it will spin slower than the sprinkler that is free to spin. The same goes for a starter which is sticky or binding.
The analogies described are very similar except that in electrical systems you will not be able to make changes or affect the components without suffering some serious consequences (to the components).

The term "Amperes" is a tag used in describing the electrical flow (current) of an electrical circuit..
A battery does not "deliver" amps to the starter as though it were offering something "unsolicited". It is more like the starter is DEMANDING the battery give it the power it needs to turn the engine. So the starter is really at the mercy of the battery as to what it receives.
Batteries are rated by their capability to furnish power described as "X number of Amps". But that rating is only true if the battery has a full charge and the battery is new.
The analogy between water pressure and voltage is pretty accurate.
In plumbing, pressure of a specific value will push a specific volume of water through a specific diameter conduit having a specific value of resistance to flow.
In electrical systems, a specific voltage value will push a specific volume of electrical current through specific size conductors where there is a specific electrical resistance.
The consequence to be faced in electrical systems where the "specifics" become "imbalanced on the low side" is heat production.
It requires adequate voltage to push sufficient amps (in response to current draw) through a conducting circuit resulting in normal operation of the circuit components as it was designed for.

Consequence of low voltage:
If you cut the voltage in half but leave the other factors the same...........the result will be heat production due to the voltage not being adequate to push those amps through the resisting component.

Consequence of insufficient amp capacity of battery:
This is what we face when we are dealing with an old battery (anything that is not brand new).
Amp capacity of a battery is relevant to its physical size (plate surface area) and the state or condition of the battery.
Imagine two 12 volt batteries. One of the batteries fits a yard tractor, the other fits a large diesel engine agriculture tractor.
Both have a voltage level of 12, but the amp capacities are vastly different between the two.
The starters of each of those tractors is matched to the amp capacity of the batteries (and vice versa).
Basically and fundamentally speaking, battery amp capacity is chosen for an application with the goal of keeping VOLTAGE DROP to a minimum when the starter load is connected to the battery.
If you connect the yard tractor starter to the yard tractor battery you can expect perhaps a 3 to 4 volt drop in battery voltage after the starter begins spinning the engine, and that is acceptable.
If.....you connect the yard tractor battery to the agriculture tractor battery, you might possibly observe a battery voltage drop of .3 to .4.
But...........if you connect the starter of the big tractor to the yard tractor battery you could realistically expect the battery voltage to drop to zero. You can also expect the yard tractor battery to explode because that kind of load would be the same as connecting a battery cable between the posts of the small battery........in essence "a dead short".
The explosion is the result of the voltage drop causing catastrophic heat build up and flash melting of the plates inside the battery case creating a steam explosion as the electrolyte vaporizes.............combined with ignition of the explosive battery gasses.

Now back to the job of trimming a lawn.
When a battery is "old", its amp capacity is less than when new, and so will not be able to meet the current draw requirements of the starter when asked to. This will cause the battery voltage to drop, further reducing the ability of the battery to supply the needed amps.
When a battery is under charged (low voltage level) there is insufficient "pressure" to push the required amps through the starter, so heat develops quickly throughout the circuit.
Subjecting the starter to a low voltage/high amp draw scenario on a regular basis will lead to cumulative damage to the starter as well as other links in the circuit (key switch, starter solenoid, cables/wires/connectors)
Always buy the largest amp capacity battery you can get that will fit in your "whatever" , keep it fully charged,........and you will have a happy life.


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RE: JOhn Deere 425 won't even crank

Monie, thank you for your excellent commentary on "batteries ". I can't imagine there being one thing left to consider. Thank you for your time to explain this very important information....paulpep68


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