Small Engines (Lawn Mowers, etc.): honda riding mower, plug caps, safety switches

Question
I have a honda H-4518 mower with a gx-650 2 cyl engine. it has a intermitent starting problem.When it dosen't start it it has no spark.I've replaced the plugs, coil,& plug caps When it starts it runs perfect. I've checked for loose wires, ground connections,ign switch,safety switches, oil switch etc. Yesterday I started it, loaded it into my truck & delivered it to the customer and it would not start! about 2 hrs after returning to my shop it started perfectly. I believe it has an electronic problem, it has an eng. control unit, a cdi unit and a comb. relay.I'm not sure how find the faulty unit. Thanks for your help, Steve  

Answer
 Hello Steve:

 There are Testers for each of the Components you have listed. However, these are not Cheap. I would Suggest you Jumper out each Safety Switch, One at a Time until you are Sure they arent the Problem. I have had Switches Test Good, but have had Shorts when Bounced and Jarred. The CDI, Eng Control Unit and Oil Switch will usually Either Not Start or Run for 15 to 20 Minutes and Quit. Then Restart after Cool Down. Im Leaning towards a Switch. I havent never had this Problem with a CDI, Eng Control or Oil Switch. If you can have them Tested, then do so. Hope this Helps.

 Good Luck

 Respectfully

 John