Cam shaft is not turning when i crank engine model 425 john deere

http://manuals.deere.com/omview/OMM173445_19/?tM=HO

Is the engine being cranked by the starter but it won't fire? You say you're getting spark? You need air, fuel, spark, and compression to start so...
Pull the air filter and see if it is blocked.
Inspect the choke plate to see if it is working properly.
Are the plugs getting wet when you try to start?
Take the gas cap off the fuel tank and try to start.
Take the plugs out and move the wires where they can't ground. Stick your finger (thumb) in one plug hole and with the throttle wide open and no choke crank the engine. Is there compression? Try the other plug hole. A compression tester would be better than a finger or thumb.
No compression can be popped push rods or a cam problem among other things.

1996.
Good luck!

as long as the lenth and diamather of the crank shaft are the same

Check your fuel filter and see if it's clogged. You might be able to blow it out with an air hose if it is.

Most John Deere dealers have a jig that the engine itself can be bolted onto and repair crank.Our dealership flat rates this repair at 2 hours but will vary among shops.

Whats your e-mail,I will send the pages you need.

Sounds more like a bad starter than a bad coil.

A failing coil usually shows up during hot weather. The engine will start and run fine, then when it heats up, it just dies out. After a few minutes, it cranks again. Then the cycle repeats itself.

The ignition module and coil pack are the same part.

Are you sure full voltage is getting to the starter? There is likely a starter solenoid between the ignition key and the starter. These solenoids can be problematic and prevent the full 12 volts from getting to the battery.

The cam has broken, this is a common problem with the 425/445. The cams are very cheap, made with plastic. Had mine replaced last year at the cost of about $300. Had water pump replaced as well.