John Deere STX 38 mower – turn key, clicks but won’t start
JD STX 38 mower – turn key, it clicks but won’t start.
| Jason | I bought a used STX 38 for $350 from CL. It appear to be very clean. Hood is not cracked, seat not torn, tires and rims look very clean. Has black mulching deck, and blades look fine too. But it doesn’t start. I turn the key from “OFF” to “RUN” position, then something clicks once. Sounds like a relay or clutch. I bypassed the seat switch and I put the breaks on. Still the same. (Battery seems to be ok) Also, I left it in my garage for a day, and I smell gas. Could it be leaking somewhere? Another question. If I attach a headlight (like a car fog lamp) to it, will the electrical system be able to handle it? Can I use 40+40 watts lamp? |
|---|---|
| Mike | Could be the starter relay under the seat near the battery. Could be the PTO switch, make sure it’s not on also! |
| strodie79 | Best way to check if it’s the starter motor that’s the problem is to put a single jumper lead from the positive lead on the battery, to the main terminal on the starter motor. If it cranks then the starter motor is fine, and the problem is either the 12 volt supply voltage to the starter solenoid (under the seat), or the solenoid itself. There were some issues with these early starter solenoids seizing, and having poor contact across the main terminals. |
| Mike | I had a similar problem, and believe it or not, when I disconnected the headlight switch, it started fine. Not sure why but it worked for me…bad switch i guess. |
| Jason | Alright. I you suggested. I directly connected battery’s plus terminal to the starter. With a little spark, it made some noise.Noise is almost like, grinding noise coming out from the gear. Are those starter motor connected to the crankshaft via gearsets? Belts? |
| Jason | When I bypass everything and connect starter directly to the battery, Starter makes sound almost like winding a socket wrench. |
| Jason | Bit more information on what I found out.I took the top cover off the engine. it exposed the fan and gearset (Big gear on Fan/Crankshaft, little pinion on starter motor). I took out the starter motor, and I applied 12V directly from the battery (Positive to the bolt stud, Negative to the case). The Motor turns. The gear turns too. (The pinion seems to have one way bearing of some sort) I put the starter motor back, and applied the 12V, and the pinion gear does not turn. Motor shaft vibrates, and the pinion gear does not rotate. I am not sure if the shaft is turning nor not. What’s wrong with the pinion? |
| Jason | Even more information I found out.I took the battery out, and took out the solenoid. When I apply 12V voltage across the top two small studs, I hear the relay clicking. I think this is OK. I already placed an order for a refurbished Starter/Bendix Drive unit for $80. Ouch. When I took the starter motor out, I could grab the pinion and power the starter and it wouldn’t do anything other than making grinding noise. I guess the one way bearing is done for. Problem is, I can’t get 12V power across the starter terminal when I turn the ignition key, even when the starter is out. Questions 1. Where is the 2Amp fuse? 2. Why are there “headlight” harness shown in the part diagram? And Where is that headlight harness? 3. How many little hidden switches that needs to be closed in order for the starter to receive the 12V power??? There is a seat switch, Neutral switch, break switch, and what else? |
| strodie79 | The starter has a pinion which runs on a worm type shaft. when you engage the starter motor, the centrifical force makes the pinion fly up the shaft and engage(mesh) with another gear that runs around the outside of the flywheel. So to answer the question, they are connected to the engine via a gear on the flywheel, but only while the motor is actually cranking |
| strodie79 | The noise could be a couple of things. Either the pinion is stripped, or the flywheel teeth are stripped, or the worm gear inside the pinion (where it slides up and down to engage)is stripped. basically, if the motor itself spins and has enough grunt, the pinion shouls fly up (very quickly) and engage it’s teeth with the flywheel’s teeth, and in turn wind over the engine. If it doesn’t do this, then the pinion has a problem on the starter motor. |
| strodie79 | see the previous post, I think I have answered this |
| strodie79 | With the starter motor installed, and connected up to the solenoid as if you were ready to start it, do the same again. Power up the small terminals. It will click again, and should crank the engine regardless of all the other switches. If it does crank, then the problem is in the wiring before the solenoid. If it doesn’t crank, the problem is in the solenoid. Sometimes they click, but the big terminals don’t bridge properly internally, so it sounds like it works, but it doesn’t make contact.The only other switch besides what you have mentioned is the PTO switch. If this has a problem with it, it functions much the same way as the other safety switches. The switch must be off to start the engine, but when they are bad, even though the switch is off, the contacts in the switch still make it think it is on, and it will not start. |
| Jason | Where is the PTO switch located?and what’s PTO stand for? |
| bontai Joe | The PTO switch is right on the dash, it’s the “power take off” switch that turns the mower deck on and off. That switch needs to be in the off position to start the tractor. |
| Jason | You mean the yellow I/O switch that looks like a car cigarette lighter? On my STX38, it’s next to the ignition key, which is next to the shifter. Is that PTO switch? So I should put it on “O” when starting the engine, correct? |
| bontai Joe | I stands for implement (if I remember correctly) and O stands for off, so it should be in the O position. |
| Jason | My STX38 is running now. I had to replace the starter unit (together with the bendix pinion gear). The one way bearing of the old starter was stripped and did not have enough torque to turn the engine over. But the new starter had hard time turning the engine over. So I removed the spark plug and turn over the engine by hand 5-6 revolutions to “free” it up – then it started without any problem. |
Tractor Videos:
It could be that the pinion is stripped or maybe the flywheel teeth are stripped, or the gear inside the pinion is gone
28 November 2008, 9:52 ampaul miltenberger:
take the spark plug out it sounds like the fuel filled the engine with gas and the engine cant turn over its common on this engine
20 February 2009, 6:47 pmvpedwards:
What the thieves at John Deere won’t tell you is to check your relay (it is under the seat on the STX 38). Over the years, because they believe in making money over serving their customers they have sold me a starter, two ignitions and a coil because I would not bring my tractor in for them to fix it. It is a part of the ignition/starting system that commonly fails and only costs fifteen dollars. Pass this on!!!
5 May 2009, 7:23 amgeorge:
jason it sounds to me like u have a ground issue.the stx38 came with the 12.5 horse kohler or the 15.5 horse kohler.from my experience of working on deeres all the years.i worked as a mechanic with deere when that machine made its way to the sales floor .i can go on for hours about the issues they had with that machine.they had drive belt problems and they were known for the electrical systems having problems.check your ground from the battery to the frame im sure you will find your problem there.and if that doesnt fix it you may have a dead cell in your battery.good luck jason
21 June 2009, 10:13 pm