My Deere L-120 has no Spark

[tcmesser]

I am looking for a little assistance with my garden tractor. After cutting the grass last week, I parked it (outdoors) for the week. Went to fire it up and the engine turns over fine but she won't start. I can see fuel flowing through the filter, but when I checked for spark, there was no fire on either side (20HP). I usually can start her up with the brake lock on, but not sitting on the tractor seat, but even sitting on the seat, no fire. Any suggestions before I call an expensive technician to make a house call?

Thanks,
Tim

 

[ctlguy]

This unit has two coils, kind of spendy upper 30's per coil. I have seen them fail on this unit. May also try looking at flywheel surface and make sure is not rusted. A little crokus cloth would take care of that.

 

[WayneB]

You might want to check the magneto. It could be shorted which would prevent any spark.

I have a L155 and was having problem with it not starting found out the magneto was shorted. replaced and it works fine.

 

[jinman]

Make sure the seat switch is not malfunctioning. Does it have an electric PTO? Is that switch engaged? Just two ideas that come to mind.

 

[ctlguy]

You might want to check the magneto. It could be shorted which would prevent any spark.

I have a L155 and was having problem with it not starting found out the magneto was shorted. replaced and it works fine.

In this application the magneto/coil is the same item

 

[Johndeere3720]

My L118 did that one and it was the battery conections. The conectors were rusted out so we just took a wire brush to them, scraped off the rust and it works great. Remove the terminals and the wires off and use the wire brush to clean the rust off. I hope this helps.

 

[deputyrpa]

Do you have a testing meter? Disconnect and check the lead to the (+) of the coil while cranking the engine and see how many volts are coming in. If less than 12 or so, then the battery is weak, or the stator is bad or the lead is shorted out. If that's good, check the coil (disconnected) between the (+) and (-) and and see if there is continuity (no resistence in Ohms). If there is resistance, the coil is bad. If there is continuity, it could be the condensor (if not ss). Hope that helps.

 

[jhwentworth]

I am looking for a little assistance with my garden tractor. After cutting the grass last week, I parked it (outdoors) for the week. Went to fire it up and the engine turns over fine but she won't start. I can see fuel flowing through the filter, but when I checked for spark, there was no fire on either side (20HP). I usually can start her up with the brake lock on, but not sitting on the tractor seat, but even sitting on the seat, no fire. Any suggestions before I call an expensive technician to make a house call?

Thanks,
Tim

Most tractors have safety interlocks on the seat, clutch/brake, and PTO, and some have a switch on the gearshift. The ignition can be killed by the mower deck (PTO) being engaged when in reverse gear, or if the seat is unoccupied and the brake isn't locked. There should be a (black?) wire going from the key switch to the ignition coil which grounds the ignition when the switch is turned off. Try disconnecting this wire. The ignition switches do go bad.

It would be unusual to have both coils fail, unless someone tried "jumping" the battery and got the polarity reversed. Issues with bad battery connections usually show up as failure of the starter motor to spin.

 

[tcmesser]

As it end up, the issue was with the safety interlock switch in the seat. Thank you all for the asistance.

Tim

 

[jhwentworth]

As it end up, the issue was with the safety interlock switch in the seat. Thank you all for the asistance.

Tim

The safety interlocks are a VERY common cause of "no start" problems. It's a good idea to verify just how your tractor behaves when the seat is empty, or the clutch/brake is not depressed, or the PTO is engaged. Try starting the machine with each condition to see what happens. With the PTO or clutch/brake active the starter motor probably won't spin, on some machines the starter won't spin if the seat is empty. Most will kill the engine if the seat is empty and the brake isn't set or the PTO is engaged. Better to know how you machine works so you can better diagnose a failure.