Small Engines (Lawn Mowers, etc.)/24hp Honda not firing


QUESTION: I have a firing issue with my Hustler Super Z mower. It is equipped with a Honda 24hp GXV670 engine. Serial# is TAE2  Gjah1007897. I can unplug the stop diode and the engine will fire indicating the coils are working. Where to go from here..?

ANSWER: Have you checked each safety switch with an ohm meter and verified they are working?

Is there a wiring diagram with your manual that you can use to locate all of the safety switches?

If one of them is not properly functioning the spark may be shorting to ground.


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QUESTION: There is one on each control arm, one on seat.
I have replaced each one on the control arms. The seat switch only kills the engine if you stand up with the clutch engaged. I have replaced all relays (3), ignition switch, stop diode, clutch switch. This is a tough one...
I am hoping you can help isolate the problem.


ANSWER: Do you have an ohm meter or digital multimeter?

Could the insulation on a ground wire have wore through causing a permanent short to ground?

I would connect a meter to the shut-off wire and the other end to ground.  Start dis-connecting switches and relays until the ground disappears.  Then re-connect one at a time until a single circuit is identified that is causing the wire to short to ground.


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

QUESTION: I have and digital multimeter.
Connect a meter to the shutoff wire (Stop diode that is connected to the coils?)
Selection on the multimeter "dc20"?

Se the meter to ohms or continuity.  Connect one end of the meter to ground or the negative battery cable.  When the key switch is in the off position there should be continuity between ground and the shut-off wire connected to the engine coil(s).  Usually there is only one wire that shuts the engine off.


Small Engines (Lawn Mowers, etc.)

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Eric A. Jones


Lawnmower Repair . Certified Master Service Technician from B&S. Have 23 years experience on B&S, Lawn Chief, Weed Eater, Echo, Peerless, Wheel Horse, Snapper, Atlas, MTD, McCulloch, Homelite and many other numerous brands. Specialize in electrical repair.


Born and raised in the midwest. Started tinkering with engines when I was about 14 on my Suzuki RM-80. I began lawn mower repair at a small hardware store. I knew absolutely nothing. I read lots of repair manuals and met an older fellow who taught me many lessons. I continued working on small engines through high school and paid my way through college working on mowers at the same hardware store. Decided to get away from the midwest and mower repair so I joined the Air Force. I repaired air traffic control electronic equipment and ended up in Hawaii where I got a part time job at Small Engine Clinic. I gained a lot of experience from the Small Engine Clinic and had a blast repairing small engines. I then took the Briggs and Stratton Master Service Technician test and earned my MST. I then traveled to Wisconsin where I attended the factory update training seminar and received formal training. Continued working on mowers part time as I completed 20 years of military. Retired from the military on a Friday and continued in the lawn and garden industry the next Monday.

MAS Aerospace Operations BA Mathematics AAS Electronic Communications AAS Electronic Technology

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