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have a john deere z425 that owner has replaced the key switch starter, voltage regulator and coils and did some wire cutting. the engine will not turn over using by jumping solenoid but there is no spark from coil. do not if the owner used the correct replacement parts. , my gut tells to replace the coils and see what happens. looking for any help to fix thanks

Hello ACF,

What is the PIN on the white sticker on the machine? What are the numbers the engine label or stamped into the top of one of the valve covers.? JD made several versions of the Z425, they are not all the same.

I hate when owners dabble with stuff before asking for help. What wires have been cut?

"will not turn over jumping the solenoid but there is no spark" Did you proofread what you wrote?

multiple problems may be here. Chase each one individually. Get the starter working, then get the ignition working. If it has an electronic module that could be the culprit. ASK the owner WHY he was monkeying with the wires. Sounds like something failed then he made things worse. Keep track of your hours and bill accordingly.

Hello sgkent,

Never had both coils fail (if it is a V-twin). They will still run, but underpowered on one coil. This one is getting interesting.

I've got several owners like this that just start swapping (Amazon) parts out of desperation and it is a real pain to undo all the experimental carnage in most cases.

Auto Doc's said:

Hello sgkent,

Never had both coils fail (if it is a V-twin). They will still run, but underpowered on one coil. This one is getting interesting.

I've got several owners like this that just start swapping (Amazon) parts out of desperation and it is a real pain to undo all the experimental carnage in most cases.

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Always not fun and causes a lot of extra that customer must pay for. And I had to ignore a customer that wanted me to sharpen a set blades on Sunday. My lord it is my only day off to rest besides I think 60 hrs a week is enough aggravation. And a computer failure doesn't help.

ACF said:

have a john deere z425 that owner has replaced the key switch starter, voltage regulator and coils and did some wire cutting. the engine will not turn over using by jumping solenoid but there is no spark from coil. do not if the owner used the correct replacement parts. , my gut tells to replace the coils and see what happens. looking for any help to fix thanks

Click to expand...

I thinking there is terminology terms problem in the OP post. He may be saying the engine cranks but will not start up running.

Disconnect the interlock relay and test. Sounds like safety circuit problem keeping the ignition coils grounded. And cut wires must be re-spliced before proper troubleshooting can occur.




Boy what a learning curve this Win 10 has and not looking forward to Win 11. Everything is different. Learning on the fly is always a challenge I am not looking for.

Auto Doc's said:

Hello ACF,

What is the PIN on the white sticker on the machine? What are the numbers the engine label or stamped into the top of one of the valve covers.? JD made several versions of the Z425, they are not all the same.

I hate when owners dabble with stuff before asking for help. What wires have been cut?

"will not turn over jumping the solenoid but there is no spark" Did you proofread what you wrote?

Click to expand...

do not have the white sticker but engine model is 40h777-0182-g5

Hello ACF,

All JD mower equipment comes with a durable product identification number (PIN). Some are fairly well hidden on the frame behind one of the rear tires on Z-Tracks.

This may help with parts sourcing. There are lots of parts variations even for this engine depending on what machine it was installed on.

Since no one is willing or able to post these, here is the schematics for the Z425 with Briggs engine.

thanks Star Tech

Did you get this running?

no but did wires traced out, it will start with help of starting fluid if solenoid post are crossed with jumper wire. with the key it will engage starter but will not turn over engine, did voltage check and not getting any voltage on the starter post of solenoid when using key, so now need to find the bad safety switch, replaced seat switch and pto switch no change so will look at the other switches

Are you getting voltage to the small trigger wire when the key is turned to the crank position? If so, it is not it is not a safety switch issue, it is a solenoid problem.

replaced solenoid no change

Do you have a multi-meter or a single bulb 12V test light. Just randomly changing parts is not diagnostics, it's a lesson in futility.

mulitmeter

Auto Doc's said:

Are you getting voltage to the small trigger wire when the key is turned to the crank position? If so, it is not it is not a safety switch issue, it is a solenoid problem.

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no voltage on white wire going to solenoid

Hello ACF,

StarTech sent you diagrams, apparently the second one is a match to your machine. Print off and study the diagram. Use it like a "road map" to steer you to where the problem is.

You also mentioned in an earlier reply that the key will engage the starter, but the starter does not turn the motor.

Has the battery been removed and tested by a parts store? Your meter can read 12 volts, but the battery can still be bad.

Voltage is only a potential to do work. It takes amperage to conduct the work. Your meter cannot test amperage that high.

used them to do trace the wires to check for any breaks in wiring, tested the battery with load tester comes up just in the good range. yes when the key is turned to start position the starter will engage fly wheel but not turn engine, but when i cross the two post on solenoid with jumper wire the engine turns over good.

Are you familiar with using a meter to do voltage drop testing?

no i am not, i am just a retired submarine A-Ganger playing with mowers

Hi ACF,

Here is an example of the voltage drop test:

https://www.bing.com/videos/rivervi...E312C6FCE7034ED0B900E312C6FCE7034ED&FORM=VIRE

The trick is power has to be flowing on the circuits with the key turned to the crank position while measuring with the DVOM. This phenomenon of seeing a voltage reading on the meter with the leads on a single cable or wire is what tricks many people.

new battery on charge

did the following test
battery positive side to cable going to solenoid
off .001 run .001 start .001
battery positive cable to starter
off 14.21 run 14.21 start 13.8
battery positive to solenoid connection that has white attached
key off 3.44 run 14.21 start 13.96
battery positive to white wire disconnected
key off .003 run 14.19 start .004
ground off .00 run .00 start peak .064

solenoid bad ?

Auto Doc's said:

Hi ACF,

Here is an example of the voltage drop test:

https://www.bing.com/videos/rivervi...E312C6FCE7034ED0B900E312C6FCE7034ED&FORM=VIRE

The trick is power has to be flowing on the circuits with the key turned to the crank position while measuring with the DVOM. This phenomenon of seeing a voltage reading on the meter with the leads on a single cable or wire is what tricks many people.

Click to expand...

Do not have a charger connected when testing but make sure the battery is good.

Only test for voltage drop with the key switch held in the crank position for each meter reading test as you move around.

Remember to only test one (the same) wire or cable at a time from end to end.

no charger new battery
battery cable to solenoid in start .002
battery to starter in start 12.90
battery to white wire on solenoid 12.88
battery to white on solenoid wire not connected to the solenoid .008

ACF said:

no charger new battery
battery cable to solenoid in start .002
battery to starter in start 12.90
battery to white wire on solenoid 12.88
battery to white on solenoid wire not connected to the solenoid .008

Click to expand...

You will need to check all safety switches working backwards from the white solenoid trigger wire if I am understanding the reading correctly.

Maybe this video will help.

it's me again
took star tech drawing # 2 sn 120001, did a continuity test on all the wires got a good long beep on all except for the ones going to the coils just got a beep then nothing, could d1 or d2 be bad, also the coils have jb weld on a post of each coil, but when i disconnect the ground wire and jump solenoid with the aid of starting fluid the engine will start, but connected will not start

also my other concern is the k2 interlock on drawing, the wires did not match the pins on the drawings when i did the test,
when key placed in run position do get a clicking in the k2 relay

tested all safety switches seat not working and right handle replaced,

did voltage check at the key switch
b position: had voltage during off, run and start positions 12.67 volts
s2 position, had voltage only in the run position 12.55 volts
s1 position, no voltage at any position
a position, voltage in run position only 12.65 volts
m position, no voltage at any key position

pto will engage in run position

thank you for taking the time to teach me and help with this problem

If S2 has voltage and S1 don't in start position then the ignition switch is probably bad or one of the wire terminals is not making contact.

And which ground wire are you referring to? Is it the 601A White wire at the engine?

And explain how the wires didn't on the K2 relay. If different in color look for the wire number print on the wires. I seen different colors used but wire has so matched to diagrams.

StarTech said:

If S2 has voltage and S1 don't in start position then the ignition switch is probably bad or one of the wire terminals is not making contact.

And which ground wire are you referring to? Is it the 601A White wire at the engine?

And explain how the wires didn't on the K2 relay. If different in color look for the wire number print on the wires. I seen different colors used but wire has so matched to diagrams.

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disconnected switch reconnected had voltage but not constant when did have power the starter would engage only, owner reported that key switch was replaced

wire 601a at engine connect checked out good continuity at c4m once it became a black wire there was no continuity, going to the wires at the coils.

the k2 relay i have the following wire connections
wire 704 gets continuity at position 87a upper left if looking from back of mower
wire 606 gets continuity at position 87 upper middle if looking from back of mower
wire 601a gets continuity at position 85 upper right if looking from back of mower
wire 420 gets continuity at lower left pin if looking from back of mower
wire 100r gets continuity at lower right pin if looking from back of mower

thanks

First the ignition switch connector must have a bad F56 - Packard - Gm - Delphi wire terminal. They like along spring hinge leading to a loose connection

Second at the connector the white wire changes over to black the female wire is probably loose or not making contact due corrosion.

100R should be on terminal 30 of the relay.

420A should be on terminal 86 of the relay

420C should also be on terminal 86 of the relay

Both are good as the relay operates and the fuel solenoid operates. Note both of these are +12vdc whenever the relay is active.

601A should be 601B at the relay and course it has continuity if the ignition off that part of the magneto kill circuit. DO NOT apply +12vdc to this circuit it will destroy both ignition coils. Plus may damage the relay, ignition switch, and associated wiring.

704 White should have continuity whenever the relay is active. It also should on terminal 86. This completes the ground circuit for the starter solenoid.

There is no 606 on the wiring diagram but 601B should connected to 87A relay terminal and 704 should be on 87 relay terminal. From your info these appear to have been reversed. Which would explain why the start solenoid isn't working.

Two things happen when you apply power to the wrong circuit. One is you let the "magic smoke" out and two, you likely created more problems than you started with.

StarTech said:

First the ignition switch connector must have a bad F56 - Packard - Gm - Delphi wire terminal. They like along spring hinge leading to a loose connection
replaced the ignition switch turns over now

Click to expand...

StarTech said:

Second at the connector the white wire changes over to black the female wire is probably loose or not making contact due corrosion.

Click to expand...

StarTech said:

had to replace the c4b connection since wires cut and pin missing on connection the wires coming out of c4b had good continuity to where i spliced the wires together, disconnected the splice and had no continuity to fuel solenoid or coils. pulled the wires from behind starter found fuel solenoid wire broken, reconnected had continuity and voltage. coil wire found no damage could the diodes be bad?

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StarTech said:

100R should be on terminal 30 of the relay.
wires are all connected to the correct pin after i was able to read numbers on relay
420A should be on terminal 86 of the relay

420C should also be on terminal 86 of the relay

Both are good as the relay operates and the fuel solenoid operates. Note both of these are +12vdc whenever the relay is active.

601A should be 601B at the relay and course it has continuity if the ignition off that part of the magneto kill circuit. DO NOT apply +12vdc to this circuit it will destroy both ignition coils. Plus may damage the relay, ignition switch, and associated wiring.

704 White should have continuity whenever the relay is active. It also should on terminal 86. This completes the ground circuit for the starter solenoid.

There is no 606 on the wiring diagram but 601B should connected to 87A relay terminal and 704 should be on 87 relay terminal. From your info these appear to have been reversed. Which would explain why the start solenoid isn't working.

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rechecked and found the wires are connected to the correct terminal

think that i need to get wiring harness for coils and it should start, once clean carb.
thank you i have learned so much from this mower and with the help from you and this site,

reconnected the wires to coils tried to start and it started, did not have to clean carb used a little starting fluid and it started up and ran. so all you guys that have the experience what would you charge this guy for all the work that was performed
again thank you for all of the help in resolving this issue. great site and people that help us