425 won't start or fire

[weeder]

I have a 1996 425 John Deere lawn tractor 20 hp Kawasaki engine FD620D. I have spark at the plugs but it shoots out air and fuel out of the top of the carb. Someone told me to get a carb kit. I did and it does the same thing. Could the timing be off? This is still a good lawn tractor I would hate to junk it maybe someone can lead me in the right direction.

Thanks Weeder

 

[beenthere]

Sure doesn't sound like a carb problem, but rather something messed up with the valves. At one time back a ways, these engines had a plastic cam. Know if yours was ever changed out?

Check with your Deere dealer and ask about your tractor. They can run the serial number and see what repairs were done, if they were properly recorded.

Too bad you rec'd poor advice on the carb.

:welcome: to TBN

 

[weeder]

Wonder why it is so hard to find out info on the web on John Deere mowers and etc.? How hard is it to check the flywheel key to see if it has sheared?

 

[Dave M7040]

Take a look at this link to a photo copy of the service manual.
http://www.google.ca/url?sa=t&rct=j...x79o4kgWNHpSgzJfqBTqXMQ&bvm=bv.93112503,d.d24

I would first check the compression. Valves are to be adjusted every 200 hours. Tight valves can cause the problems you are experiencing.
The manual talks about a pulser coil going bad. This could compromise the timing.
Remove the valve covers and watch the valves as the engine rotates. Are all moving up and down as they should.
Dave M7040

 

[olllotj]

The plastic cam gear likes to go on those. Pull the valve covers and watch as you turn it over. I bet you have no valve movement whatsoever. meaning its time for a new cam. Replacements are steel.