Engine will not crank on lt 1046. New battery. Seat switch is working. Seems like the clutch safety switch. Any ideas. thanks. Bill

You bypassed the start safety and it starts/runs so battery and starter work along with kill. The first fault symptom is it will not crank engine?


If yes, suggest you troubleshoot the no crank. The typical start safety interlock is brake ON (clutch disengaged) and PTO off (some require seat occupied). You will need trace the the start engine circuit beginning with the S pole of the start switch through the entire safety interlock. Likely this will require a schematic of the interlock circuit as it is mfg specific.


What's is the make/model?

When I turn the key nothing happens.
There are several elements that go into cranking (turning over) the engine.

1. Battery
2. Fuse
3. Key Switch (and wiring)
4. Starter Solenoid and wires
5. Starter motor

To begin with check the fuse. It's a 20amp car style fuse located under the hood near the battery.

If the fuse does not fix the problem let's move on to the battery. The quickest way to make your initial check of the entire starting system and particularly the battery is to get a jump. Yep, get some jumper cables and jump the mower off your car. Turn the key and try to start it in the normal fashion(normal meaning YOU in the seat, PTO off, BRAKE pressed all the way down). If it starts cool! It is likely a bad battery.

• Charge the battery for a few hours, on a charger.
• Then perform a voltage measurement of the battery.
• Switch a volt meter to DC Volts and clip it to the battery. It should read between 12-13 volts. If not the battery is suspect. If it is 12-13 volts see if it will crank, but continue to watch the volts. If they drop below 10ish volts, the battery may have a bad cell.

Now let's check the starting system while bypassing all the safety switches and wiring. How? You can perform this test simply by jumping the starter solenoid. Hold a wrench or fat screwdriver across the two large posts of the starter solenoid. This bypasses the key switch and all safety devices and directly drives the starter. Your starter will crank if the battery and starter are good, the wires and connections are good, and the engine is not locked up. Don't crank it for more than a couple seconds. You just want to verify the battery and the starter are both in good shape. (The engine will crank but not start during this test as long as the key is off, or if the safety switches or wiring are damaged, or if the safety switches are in the no start/run positions.)

If the starter cranks try one more test. Run a small jumper wire from the positive post of the battery to the little terminal on the solenoid. You may have to take the small wire off the positive terminal of the starter solenoid, in order to do this. When you apply this current from the battery to the positive terminal it should make the solenoid activate and the starter crank. This test bypasses the key switch and shows you the starter system is working. You could do this test first; if it works you do not need to do the basic jump test.

If these tests cause the engine to crank, but it will not crank with the key, then you know you have a problem somewhere in your starter wiring, safety switch system, fuse, or in your Key Switch. Of course you did check the battery terminals for tight, clean connections, right?

Most modern riding mowers have the following 4 safety switches:

• Seat switch
• PTO switch
• Reverse switch (RIS) and Reverse Relay (RIO)
• Brake/Clutch switch

If you need detailed instruction for testing your wiring and safety system, I will need your complete machine info.

• Make
• Model
• Year
• Engine Model
• Transmission Model
• Deck Size.

On a John Deere (100 series) the starting current flows through the following items in this order:

1. Battery to Fuse then to the Key Switch.
2. With key switch in the start position, the current flows from the Key Switch to PTO.
3. With PTO off, current flows from the PTO to Brake/Clutch Switch
4. With Brake/Clutch Pedal all the way down, the current flows through the switch to the starter solenoid.
5. If the Starter Solenoid is in good shape, the solenoid connects the battery to the Starter and the engine cranks. Cranking does not mean running; it just means the engine turns over. Running is dependent on many other systems.

Those components are all part of the cranking/starting system. They can prevent the Starter Motor from cranking when you turn the Key Switch. You can trace the voltage with a multi-meter. Connect the black lead to ground and look for 12 volts at each successive switch. If the voltage disappears at one particular step, there is your suspect.

Electrical elements that are NOT part of the starting system:
The RIO is the Reverse Implement Option. It is a switch that latches and stays latched under certain conditions. It is activated by the RIS. The RIS is the Reverse Implement Switch. It activates the RIO.These switches are called slightly different names by different manufacturer, but they all do the same thing. These two separate components work to allow the blades to cut while you are backing up (without killing the engine). They have nothing to do with the starting system.

The Seat and the RIO (the reverse latch not the button) switches are tied into the engine kill system. They provide a ground path for grounding the Coil. This same system controls the fuel shut off valve beneath the carburetor. The Seat and RIO can keep the engine from running but they will not prevent the Starter Motor from cranking. Therefore, if you turn the key and nothing happens, the problem has nothing to do with the Seat and Reverse switches.

Note: With the Key in the RUN position, power flows from the Key Switch to the Hour Meter, then to the RIO latch relay (not the RIS button), then to the fuel shut off solenoid. If you do not hear the Fuel Shut off Solenoid clicking on and off when you turn the Key Switch from off to run, there may be a problem in this circuit; including a possible problem in the Hour Meter. Of course none of this affects the cranking circuit. Your engine will still crank, it just won't start and run.

When I turn the key nothing happens.
There are several elements that go into cranking (turning over) the engine.

1. Battery
2. Fuse
3. Key Switch (and wiring)
4. Starter Solenoid and wires
5. Starter motor

Let's start with the battery. The quickest way to make your initial check of the entire starting system and particularly the battery is to get a jump. Yep, get some jumper cables and jump the mower off your car. Turn the key and try to start it in the normal fashion. If it starts cool! It is likely a bad battery.

• Charge the battery for a few hours, on a charger.
• Then perform a voltage measurement of the battery.
• Switch a volt meter to DC Volts and clip it to the battery. It should read between 12-13 volts. If not the battery is suspect.

Now let's check the starting system while bypassing all the safety switches and wiring. How? You can perform this test simply by jumping the starter solenoid. Hold a wrench or fat screwdriver across the two large posts of the starter solenoid. This bypasses the key switch and all safety devices and directly drives the starter. Your starter will crank if the battery and starter are good, the wires and connections are good, and the engine is not locked up. Don't crank it for more that a couple seconds. You just want to verify the battery and the starter are both in good shape. (The engine will crank but not start during this test if the key is off, or if the safety switches or wiring are damaged, or if the safety switches are in the no start/run positions.)

If the starter cranks try one more test. Run a small jumper wire from the positive post of the battery to the little terminal on the solenoid. You may have to take the small wire off the terminal, on the starter solenoid, in order to do this. When you apply this current from the battery to the terminal it should make the solenoid activate and the starter crank. This test bypasses the key switch and shows you the starter system is working. You could do this test first; if it works you do not need to do the basic jump test.

If these tests cause the engine to crank, but it will not crank with the key, then you know you have a problem somewhere in your starter wiring, safety switch system, fuse, or in your Key Switch. Of course you did check the battery terminals for good connection, right?

Most modern riding mowers have the following safety switches:

• Seat switch
• PTO switch
• Reverse switch (RIS) and Reverse Relay (RIO)
• Brake/Clutch switch

If you need detailed instruction for testing your wiring and safety system, I will need your complete machine info.

• Make
• Model
• Year
• Engine Model
• Transmission Model
• Deck Size.

On a John Deere (100 series) the starting current flows through the following items in this order:

1. Battery to Fuse then to the Key Switch.
2. With key switch in the start position, the current flows from the Key Switch to PTO.
3. With PTO off, current flows from the PTO to Brake/Clutch
4. With Brake/Clutch Pedal all the way down, the current flows to the starter solenoid.
5. If the Starter Solenoid is in good shape, the solenoid connects the battery to the Starter and the engine cranks. Cranking does not mean running; it just means the engine turns over. Running is dependent on many other systems.

That list of components are all part of the cranking/starting system. They can prevent the Starter Motor from cranking when you turn the Key Switch. You can trace the voltage with a multi meter.Connect the black lead to ground and look for 12 volts on each successive step.If the voltage disappears at one particular step, there is your suspect.

Electrical elements that are NOT part of the starting system:
The RIO is the Reverse Implement Option. It is a switch that latches and stays latched under certain conditions. It is activated by the RIS. The RIS is the Reverse Implement Switch. It activates the RIO. These two separate components work to allow the blades to cut while you are backing up (without killing the engine). They have nothing to do with the starting system.

The Seat and the RIO (the reverse latch not the button) switches are tied into the engine kill system.They provide a ground path for grounding the Coil. This same system controls the fuel shut off valve beneath the carburetor. The Seat and RIO can keep the engine from running but they will not prevent the Starter Motor from cranking. Therefore, if you turn the key and nothing happens, the problem has nothing to do with the Seat and Reverse switches.

Note: With the Key in the RUN position, power flows from the Key Switch to the Hour Meter, then to the RIO latch relay (not the RIS button), then to the fuel shut off solenoid. If you do not hear the Fuel Shut off Solenoid clicking on and off when you turn the Key Switch from off to run, there may be a problem in this circuit; including a possible problem in the Hour Meter. Of course none of this affects the cranking circuit. Your engine will still crank, it just won't run.

There is usually one in the seat.

When I turn the key nothing happens.
There are several elements that go into cranking (turning over) the engine.

1. Battery
2. Fuse
3. Key Switch (and wiring)
4. Starter Solenoid
5. Starter motor

Let's start with the battery. The quickest way to make your initial check of the entire starting system and particularly the battery is to get a jump. Yep, get some jumper cables and jump the mower off your car. Turn the key and try to start it in the normal fashion. If it starts cool! It is likely a bad battery.

• Charge the battery for a few hours, on a charger.
• Then perform a voltage measurement of the battery.
• Switch a volt meter to DC Volts and clip it to the battery. It should read between 12-13 volts. If not the battery is suspect.

Now let's check the starting system while bypassing all the safety switches and wiring. How? You can perform this test simply by jumping the starter. Hold a wrench or fat screwdriver across the two large posts of the starter solenoid. This bypasses the key switch and all safety devices and directly drives the starter. Your starter will crank if the battery and starter are good and the engine is not locked up. Don't crank it for more that a couple seconds. You just want to verify the battery and the starter are both in good shape. (The engine will crank but not start during this test if the key is off, or if the safety switches and wiring are damaged, or in the no start/run positions.)

If the starter cranks try one more test. Run a small jumper wire from the positive post of the battery to the little terminal on the solenoid. You may have to take the small wire off the terminal, on the starter solenoid, in order to do this. When you apply this current from the battery to the terminal it should make the solenoid activate and the starter crank. This test bypasses the key switch and shows you the starter system is working. You could do this test first, if it works you do not need to do the first more basic test.

If these tests cause the engine to crank, but it will not crank with the key, then you know that you have a problem somewhere in your starter wiring and safety switch system.

Most modern riding mowers have the following safety switches:

• Seat switch
• PTO switch
• Reverse switch (RIS) and Reverse Relay (RIO)
• Brake/Clutch switch

If you need detailed instruction for testing your wiring and safety system, I will need your complete machine info.

• Make
• Model
• Year
• Engine Model
• Transmission Model
• Deck Size.

On a John Deere (100 series) the starting current flows through the following items in this order:

1. Battery to Fuse then to the Key Switch.
2. With key switch in the start position, Key Switch to PTO.
3. With PTO off, PTO to Brake/Clutch
4. With Brake/Clutch Pedal all the way down, the current flows to the starter solenoid.
5. If the Starter Solenoid is in good shape, the solenoid connects the battery to the Starter and the engine cranks. Cranking does not mean running; it just means the engine turns over. Running is dependent on many other systems.

This list of components are all part of the cranking/starting system. They can prevent the Starter Motor from cranking when you turn the Key Switch.

The RIO is the Reverse Implement Option. It is a switch that latches and stays latched under certain conditions. It is activated by the RIS. The RIS is the Reverse Implement Switch. It activates the RIO. These two separate components work to allow the blades to spin while going backwards (without killing the engine)

The Seat and the RIO (the reverse latch not the button) are tied into the engine kill system by grounding the Coil. This same system controls the fuel shut off value beneath the carburetor. The Seat and RIO can keep the engine from running but they will not prevent the Starter Motor from cranking. Therefore, it you turn the key and nothing happens, it has nothing to do with the Seat and Reverse switches.

Note: In the run position, from the Key Switch, power flows to the Hour Meter, then to the RIO latch relay (not the RIS button), then to the fuel shut off solenoid. If you do not hear the Fuel Shut off Solenoid clicking on and off when you turn the Key Switch from off to run, there may be a problem in this circuit; including a possible problem in the Hour Meter. Of course none of this affects the cranking circuit. Your engine will still crank, it just won't run.

you have a safty switch problem you have 4 to 6 switchs the easest way to test them ,startin with the seat get a ohms metter they are open or noramly closed

Bill, not sure, but, the engine will not crank with the clutch engaged, I don't know what happened, but sounds like the clutch switch went out and took the mower with it. Take the wires apart between the ignition and the clutch and hot wire them to see if the clutch jumps. If it is working, then make sure it is off, or disconnected and try to start it, then take it from there, if it starts, you know it is the switch. If it doesn't start, then you can go look at other safety switches. make sure it is neutral, mower off, driver in seat, clutch in, etc, Hope this helps.

Check the wire connector under the seat to the seat safety switch, it may be partially or completely unplugged. If it is firmly connected, temporarily disconnect it and jump across the two terminals in the connector and see if everything works properly. If all works, replace the switch

Check to make sure battery is above 12.3 volts, secondly bypass the solenoid to the starter by using jumper cables and see if the starter works, if so, you sureley have a safety switch problem, I beleive you have five on this model,
good luck

the seat switch is the problem. the switch itself could be bad, but usually theproblem is that the connector is just not plugged in all the way [by the way, trying to bypass the switch by inserting the wire doesn't work because there is a "switch" inside the connector to prevent you from doing just what you did]