I have a John Deere 425 tractor.new plugs,new ignition module on right side.Still no spark to plug on right side.

I have a John Deere 425 tractor.new plugs,new ignition module on right side.Still no spark to plug on right side.

There is spark to left side.Engine runs,but no power on a pull.

Hi,
You have a fairly difficult machine to troubleshoot. It is a Kawasaki FD620 carbureted engine that uses a battery-energized ignition. I am unable to give any JD service links, but am able to give you one for the engine. It is:
"K&T Parts House Lawn Mower Parts and Chain Saw & Trimmer Parts" (http://www.mymowerparts.com/pdf/Kawasaki-Service-and-Repair-Manuals/)
And pick the FD620-FD661 manual.
It is a large file of 12.7 MB and 166 pages. Electrical is section 7. Start at page 108 where it shows plugs, plug caps, trigger coils, ignition coils and control module. I would check the resistance of the plug caps, 5 K ohms and should be cast into them. The triggers rarely go bad so move on to the coils which should each have 12 V (battery voltage) at the yellow/white wires (page 111.) I have a feeling this is where you will see a problem. The coils rarely give problems either. If you have battery voltage at both coils, it is likely the module if it is engine related. Unfortunately the only way to verify this is to isolate the engine by unplugging the engine from the rest of the machine. This means that you have to supply battery voltage to the coils and module that does not go through the rest of the machine. I have always done it by jumpering from the key switch module (right side inside and behind the dash.)
Good luck.
Peace,
Clarke

Check the time delay module , little black box left side of engine , about 1 inch by 2 inch.
Luck

Hi,
I agree if it has one. Some have one that looks about capacitor(cylindrical with three wires, sbout 1/2" in diameter and 1" long) and that could be a culprit. Only newer engines have it, older ones use the control module. Newer ones have both.
Peace,
Clarke