Small Engines (Lawn Mowers, etc.): John Deere 175 has no spark, safety switches, spade terminal

Question
QUESTION: Hi Eric,

I have been beating my head against a wall and continue to end up empty.  The engine is a Kawasaki 420V and I just cant get it to start..Occasionally it will backfire but rarely.  I am getting fuel and completely went through the carb.  I am unable to observe spark at the plug and have checked grounds and changed out igniter and ignition coil.  I  have also by-passed all the safety switches...I can't imagine what is left.  any recommendations would be welcome.  cheers,  Dan

ANSWER: Do you have the service manual?

http://www3.kawpowr.com/enginesecure/ServiceManuals/FC290V.pdf

I suspect there is a safety switch problem.  The best method to quickly identify a mower chasis problem or engine spark problem is to isolate the engine from the mower chasis.  

There will be a wire connected to the engine for the engine shut-off.  Dis-connect this wire and check for spark.  If you have spark then there is a safety switch or wire issue.  

The shut-off wire is usually connected via a spade terminal but I have seen a few connected to a post.

Let me know if you have trouble finding the engine shut-off wire.

Eric

---------- FOLLOW-UP ----------

QUESTION: Hi Eric,
Thanks for your help.  I have the engine started but do not understand it.   If you look at diagram on page 6 of the service manual it shows 2 wires coming from the control module (igniter) marked E.  One of these goes to the ignition coil the other appears to go to the engine key starter module.  I disconnected this wire going to the key starter and the engine started on the first try.  I need to understand what this wire is so I can look further for the problem and correct it.  would appreciate your insight here.  by the way, the service manual was great.  many thanks.

Cheers

Dan

Answer
This is the engine shut-off wire.  When you turn the key off pin A shorts pin B to ground and killing the spark.

My bet, based on your troubleshooting, is there is something wrong with one of the safety switches.  Have you tracked down each safety switch to see if they are working properly?  You can start at the key switch and track each wire to each safety switch.

You may run into a control relay or module.  

Let me know what you find on the safety switch.

Eric