I have a John Deere LX172 tractor mower that will not start. The motor cranks fine but the fuel switch is not "clicking" on when the key is turned on. I pulled the plug to make sure no fuel was going to the cylinder and while I had it out I checked & no "fire" was reaching the plug. I am reasonably certain the plug & plug wire are okay. Fuses are fine.Could this be the key board that allows the engine to crank but has something wrong with it to not allow the fuel switch to turn on nor fire to reach the plug? Or could there be another problem common to both?
Make: John Deere
Model: LX 172 lawn tractor
I ran a wire from the battery to the fuel switch & could hear it "click" on. I tried grounding the plug against the engine where I could see the tip of the plug and it was not firing. I tried another plug with the same result. I then tried a screw driver where the plug clamps into the plug wire and still no fire.
it is most likely that the fuel solenoid is sticking because there was sme fuel left in the carburetor while it was in storage.
This happens quite often. The old fuel turns to gum and varnish in the carburetor bowl and also in and around the fuel solenoid. It is nearly impossible to get these fuel solenoids to work once thi ha happenned so they usually have to be replaced.
You can check the fuel solenoid by taking off of the carburetor and then using a battery, (you can even use a 9 volt battery if you like) take a wire form the negative post of the battery and hold it to the outside of the solenoid. Then take a wire from the POSITIVE post of the battery and attatch it to the wire of the fuel solenoid.
If it clicks like it is supposed top, then there is a good chance that the solenoid is good.......not always,though.
Why is that? because some of these fuel solenoids have a rubber tip on them and the rubber tip sometimes gets soft. When this happens, this rubber tip will sometimes com off of the fuel solenoid and stay lodged in the carburetor when it is supposed to be pulled away. But when you take the solenoid out, it miraculously gets stuck back on the end of the solenoid where it is supposed to be. Check this rubber tip to see that it is stuck on the end of the fuel solenoid and that it is not loose. DO NOT PULL TOO HARD on this rubber tip!!!!! because if you pull this rubber tip off, then the solenoid will have to be replaced. If it comes off with minimal pressure, then it was bad anyway.
I hope that this gives you enough to try for now.
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I do not know if you did not receive my entire question but I wrote that I did run a wire to the solenoid & it "clicked". The plug is not getting fire either. The plug is fine. There is no fire to it. Would the problem be in the key board in that it is not turning the fuel solenoid on and not getting power to the plug, but the motor will still crank fine?
NOt ususally, but you caqn never rule it out.
If you take the solenoid out and look at the end of the soleoind ans see if the rubber tip is loose. IF it is, then it most likely is bad.
Also I would trace the wire that goes from the solenoid all the way up to the dash.
Many times there is a connector in the wire, sometimes 2 different connectors....... and if ione of them is not making contact or is even slightly corroded, it will cause this isse.
The fuel solenoid system is completely different from the ignition system that gets fire to the plug.
If you are having BOTH problems, then they are separate issues.
It you are not getting fire, then it is likely a safety switch that is not operating properly. Usually the seat switch. Or a wire leading to the seat switch. It also could be int the PTO switch.
If all the safety are working correctly, then it is likely that the ignition coil has gone bad.
Although it is possible, it is unlikely that both of these systems have gone bad a the same time.
One way to tell if the engine is working correctly other than the fuel system is to take the air filter off and dribble a small amount of fuel into the air intke of the carburetor and try to start it. If it starts or even fires, then that tells you that the ONLY problem that you have is the fuel system.
If you are NOT sitting on the seat when you are trying to check the spark, then you will not get spark.
I Own a Lawn Mower Sales and service business (37years). Have 2-cycle and 4-cycle certification.