Scotts 1642h riding mower Ignition Switch, Seat Switch or Wiring Problem?

yes, you most likely have a bad seat switch (operator presence switch) check this first.

Ensure that all electrical connections are tight, especially the grounds.

check the fuses taped to the harness

When the ignition key is turned to the start position you should have a 12 volt supply to the low tention wire at the solinoid, if not you need to check if there is a 12 volt supply to the back of the ignition switch, if not there is a break in the wiring to one of these components, also check that there is a good eart to the chassis from the black battary leed.

check the safety switch on the clutch/brake pedal

You will have at least 2 safety switches. One is the clutch/brake pedal activitated and the other is the seat switch. It sounds like the clutch/brake pedal switch is not allowing the starter to engage the flywheel and start the mower. Check for the switch under the footrest or near the back of the mower. Should be easy to find. Check it with an ohm meter and verify it is working. you could use a wire with 2 aligator clips to jump the switch but dont make this a permanent solution. Replace the switch if it is bad. One thing to consider is the ignition switch. Since you can jump the solenoid and the engine turns but wont run, you may have no power to the ignition/coil to fire a spark to the sparkplug. You need to turn the key to RUN and then jump the solenoid to confirm this. I think it will be one of those as the seat switch only kills the motor if the deck is engaged and the seat raises up. Let us know.

Hello,
My name is Dane and I am going to assist you in solving your problem. However, I would ask that you do one check for me before we go to the seat switch procedure. Please find the starter solenoid on your mower. Make sure that the 2 large cables (1 coming from the battery and 1 going to the starter) are clean and tight. Make sure that your 1 (possibly 2) wires going from your switch to your solenoid are also clean and secure. Use a volt meter on DC volts, or a test light and check the small lead on the solenoid and make sure that when the parking brake is on, transmission in neutral, and the Deck PTO is off, that you are getting 12VDC when the key switch is turned to the start position. If you have a 2-wire system, 1 of them is for ground only. 1 of the 2 wires should get 12VDC. If you get 12VDC at the small terminal of the solenoid, but no power to your starter, the solenoid is bad.

But you probably have a problem with the seat safety switch on your lawn mower. The seat safety switch makes sure that if you are ever thrown from your mower, the engine will die.

You should check under the seat of your mower and locate a small square box with normally 2 wires connected to the end of it. While looking at the switch, press down on the back of your seat and make sure your seat is activating the switch. If not, you must get the switch correctly positioned so it makes contact and pushes the button. If you found nothing wrong there, go to the next step.

Make sure the 2 wires are connected and the wiring is in good shape. Disconnect the wires from the switch and make sure there isn't any corrosion on the terminals of the switch or the connector. After you have done this, reconnect the switch and try again to see if the mower will start.

If not, disconnect the switch again and place a jumper wire between the 2 prongs of the connector and tape them so they will not ground out on the frame. Start your mower and see if it operates correctly. If so, you have got a bad seat safety switch and it needs to be replaced. This was only a troubleshooting procedure. You should never operate a mower with this switch disconnected, because you could be seriously injured. Go buy a new switch and replace it. You will need the make, model and serial number of the mower in order to get parts. I hope I've helped! Thank you! Dane

Check your seat switch and brake switch for loose wires.Most likely brake switch do to no spark at plugs,see if PTO switch/lever isnt on.

Sounds like you are on the right path, maybe some wires on the ignition were replaced backward, and you are sending +12v directly to ground? Does it blow right away?

I have to replace the belt part number m124895 on a Scotts riding mower.I need the belt configuration,since i bought it used.
Please help