Repairs John Deere M 425 no spark

[whatzup69]

Back story I was given the JD M00425A090001 mower with a 20hp V twin kawasaki motor it had been sitting out side for several years. I cleaned the fuel system. Got it running. My wife got sick so lawn mower sat for a year. When I went to crank it no luck. I cleaned fuel system. Checked for spark no spark next checked safety switches so I over rode all safety switches. I isolated the motor from the wire harness. Still no spark. I purchased a voltage doubler and a new meter ohmed the crank triggers, service manual states the ohm between 90-130 reads 125. checked voltage with the doubler should read 3.6 v I only get .428 on one and .460 ac on the other .567 and 0486 dc. What is the chance both crank triggers go bad at the same time. Could it be the delay module bad. Can the delay module be removed. I need help Thank you.

 

[bertsmobile1]

:welcome:

So lets get some basics out of the way.
I assume you have the FD625D engine with a full electronic controlled ignition.
These engine need battery voltage to make a spark so you can not just pull all the wires off like a simple magneto engine.
The two coils outside the flywheel are simply triggers and produce a very tiny amount of power to switch the transistors in the control module which then sends battery voltage to the ignition coils.

If the engine is rotating fast enough alternator output can replace battery voltage, but that depends upon the condition of the voltage regulator.

What manual are you using ?
It helps greatly if we are all singing from the same song book.

And what was the purpose of the voltage doubler ?
I can not see where it would make a difference .

 

[whatzup69]

:welcome:

So lets get some basics out of the way.
I assume you have the FD625D engine with a full electronic controlled ignition.
These engine need battery voltage to make a spark so you can not just pull all the wires off like a simple magneto engine.
The two coils outside the flywheel are simply triggers and produce a very tiny amount of power to switch the transistors in the control module which then sends battery voltage to the ignition coils.

If the engine is rotating fast enough alternator output can replace battery voltage, but that depends upon the condition of the voltage regulator.

What manual are you using ?
It helps greatly if we are all singing from the same song book.

And what was the purpose of the voltage doubler ?
I can not see where it would make a difference .

The motor family is 1KAXS617CA I cannot find a model number on the motor it is a 2001 model I am using a Kawasaki 3010 mule service manual it is the same motor. I have disconnected the wire harness from the mower powering the harness of the motor from the battery. The doubler is to make a digital meter reed the voltage from the triggers. It has a delay module that retards the timing I think not positive. The triggers out put goes to the delay module from the delay to the Igniter.

 

[bertsmobile1]

The output from any coil & magnet set up is dependent upon two things
1) the strength of the magnetic field
2) the speed that the magnet passes the coil

The strength is altered by moving the coil closer or further away from the magnets

As the speed of the magnet passing the coil increases so the voltage increases.
This is one method that the module uses to alter the spark timing.
At cranking speeds the voltage will be very low
Did you test it plugs in or plugs out ?
The 4 V listed is peak at 3600 rpm, not cranking speeds.
Note the manual says RUN the engine, not CRANK the engine for this test.
It also mentions to have fully charged battery.
If you get the same readings from both them then most likely they are fine.
If anything has gone bad it would be the magnet in the flywheel,

Use a pair of thin jumpers connected directly to the spark plug coils.
Hook one up and BRUSH the other past .
If you get a spark then the coil is fine.
The spark will be very weak because when you flick, the dwell time is very short
I use 2 x 9V transistor batteries in series ( 18V ) for this test to avoid the chance of burning the coil wires.
According to the service information the primary voltage should be around 260 V.

The full engine manual will serve you better.
And the best engine manual will be found in the JD technical manual rather than from Kawasaki.

There are 3 variations according to your mower serial number
As for the delay module. it delays the shut down function, not the start up function.

The theory is the fuel shut down solenoid closes first then a couple of revolutions latter the spark stops so there is no unburned fuel passing through the engine into the atmosphere which according to the EPA will cause all life on the planet to die.

 

[whatzup69]

The output from any coil & magnet set up is dependent upon two things
1) the strength of the magnetic field
2) the speed that the magnet passes the coil

The strength is altered by moving the coil closer or further away from the magnets

As the speed of the magnet passing the coil increases so the voltage increases.
This is one method that the module uses to alter the spark timing.
At cranking speeds the voltage will be very low
Did you test it plugs in or plugs out ?
The 4 V listed is peak at 3600 rpm, not cranking speeds.
Note the manual says RUN the engine, not CRANK the engine for this test.
It also mentions to have fully charged battery.
If you get the same readings from both them then most likely they are fine.
If anything has gone bad it would be the magnet in the flywheel,

Use a pair of thin jumpers connected directly to the spark plug coils.
Hook one up and BRUSH the other past .
If you get a spark then the coil is fine.
The spark will be very weak because when you flick, the dwell time is very short
I use 2 x 9V transistor batteries in series ( 18V ) for this test to avoid the chance of burning the coil wires.
According to the service information the primary voltage should be around 260 V.

The full engine manual will serve you better.
And the best engine manual will be found in the JD technical manual rather than from Kawasaki.

There are 3 variations according to your mower serial number
As for the delay module. it delays the shut down function, not the start up function.

The theory is the fuel shut down solenoid closes first then a couple of revolutions latter the spark stops so there is no unburned fuel passing through the engine into the atmosphere which according to the EPA will cause all life on the planet to die.

I did have the spark plugs in and spun the engine over for about 5 seconds. as for the flywheel I do not see a magnet or a place the magnet should go on the out side of the fly wheel. The battery is fully charged. the voltage that I get from the trigger coils is very close to the same on both. (PS the EPA is full of you know what)

 

[bertsmobile1]

Try it with the spark plugs out so the engine is spinning faster.
The spark timing system used on those engines is quite complicated.
Fairly sure there is a magnet in the flywheel.
Try a nail to see if it is attracted to the flywheel.
The manual uses the term "Reluctor" which is tech speak for a magnet, unless the timing coils are energised.
It does not have to be very strong as it is only needed to make a timing signal, not generate the energy for the spark.
This might be helpful.

View attachment 425 .pdf

 

[bertsmobile1]

looks like you will need the entire ignition section.

View attachment 425 ignition.pdf

Only the relevant section can be uploaded because the entire manual is just short of 1000 pages.
Note you need to use the bit that covers your serial number ( off the ID tag )

 

[whatzup69]

Thank You. I will work on this in the morning.

 

[bke]

I would look at the time delay module. When my 425 would crank over but not start. I put a new time module in and back to running. Pretty easy to put a new one in.