porschpow 7 #1 Posted June 21, 2021 Good Morning Folks, My wife cut the lawn (well....weeds, LOL) and after she got done she turned the machine off and parked it. Early evening, I am cleaning things up and noticed that it wouldn't start. I turn the ignition, lights come on, gauges work, but it didn't even turn (crank). I checked to make sure it is in neutral and the PTO is off. I also check the fuses and the the wiring in front of the battery. Everything looks good. I jumped the terminals in the starter and it jumped (sparked). I am at a loss here. My neighbors (and wife, lol) are saying to get rid of the tractor and I am still defending the old war wagon! Share this post Link to post Share on other sites
Wheel Horse 3D 3,619 #2 Posted June 21, 2021 Sounds like another instance of one of the safety switches going bad. Not sure why this happens so mysteriously. Seems to happen usually that tractor is fine one run, and the next nothin. 1 Share this post Link to post Share on other sites
squonk 38,563 #3 Posted June 21, 2021 Check the 9 pin molex Connector (White plastic) near the fuse box. Common issue with burnt and corroded pins. Share this post Link to post Share on other sites
seuadr 488 #4 Posted June 21, 2021 4 minutes ago, Wheel Horse 3D said: Sounds like another instance of one of the safety switches going bad. Not sure why this happens so mysteriously. Seems to happen usually that tractor is fine one run, and the next nothin. agreed. i made a jumper wire for these switches so they are quick and easy to test, just 2 male connectors on a short piece of wire - can jump out any one switch quickly and easily to test. Share this post Link to post Share on other sites
porschpow 7 #5 Posted June 21, 2021 Ok! So the Seat safety switch has been "overidden" before I got the tractor. The only two I could think of is the neutral safety switch and the PTO. The neutral safety switch I found, but the PTO I was unable to find! As for the 9 pin Molex connector, it appears a couple of wires has been bypassed, but from what I see, I don't see anything burnt. I will take the connector apart and get a better look. Share this post Link to post Share on other sites
Handy Don 10,439 #6 Posted June 21, 2021 Never easy to start with undocumented modifications! Any of the mods could be corroded and failing to make good contact. I'd even give a look to the connections at the starter switch! Share this post Link to post Share on other sites
Wheel Horse 3D 3,619 #7 Posted June 21, 2021 1 minute ago, Handy Don said: Never easy to start with undocumented modifications! Any of the mods could be corroded and failing to make good contact. I'd even give a look to the connections at the starter switch! Well said, It could very easily be one of the previous bypasses has some oxidization or even wiggled loose a bit. I rely on my multimeter rather than my eye. It'll find stuff I never can see. 1 Share this post Link to post Share on other sites
chip61 655 #8 Posted June 21, 2021 Occasionally on my 416H I've had to move my motion lever or the pto lever to engage the safety switch. They don't always return to position to close the safety switch and need a little persuasion. 2 Share this post Link to post Share on other sites
porschpow 7 #9 Posted June 21, 2021 Does anyone know where the PTO safety switch is on the 520H? Share this post Link to post Share on other sites
roadapples 6,980 #10 Posted June 21, 2021 Hold the key on and wiggle the wires going up to the fuses.... 1 Share this post Link to post Share on other sites
porschpow 7 #11 Posted June 21, 2021 1 minute ago, roadapples said: Hold the key on and wiggle the wires going up to the fuses.... ???? I don't quite understand. Turn the Key to crank while wiggling the wires going to the fuse block (on the underside)? Share this post Link to post Share on other sites
Handy Don 10,439 #13 Posted June 21, 2021 The PTO switches (there are two in a "twinned" arrangement) are just above the pivot point for the lever, inside the hood stand next to the battery. They are not easily seen unless the battery has been removed. Share this post Link to post Share on other sites
Pollack Pete 2,273 #14 Posted June 21, 2021 Ah,just another reason to not allow a woman to get near anything mechanical.I've always found here,that if something here is going to break,the Squaw has usually just been using it.Coincidence???? Maybe.Maybe not.I call her the jinx.She gets mad as hell. 3 Share this post Link to post Share on other sites
Handy Don 10,439 #15 Posted June 21, 2021 PTO switches are here stacked one on top of the other below the throttle cable. 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,441 #16 Posted June 21, 2021 Download this file. The starter circuit has it's own diagram. Share this post Link to post Share on other sites
porschpow 7 #17 Posted June 22, 2021 14 hours ago, gwest_ca said: Download this file. The starter circuit has it's own diagram. Thank you Share this post Link to post Share on other sites
porschpow 7 #18 Posted June 22, 2021 16 hours ago, Handy Don said: PTO switches are here stacked one on top of the other below the throttle cable. Thank you! Ok, I know where that is at. On my 520H (1996-1997), I have the fuse block right on top of the PTO switch. Why where they be two of these switches for the PTO? Share this post Link to post Share on other sites
Handy Don 10,439 #19 Posted June 22, 2021 Great! One switch locks out the starter. The other kills the engine if the operator isn't in the seat. Share this post Link to post Share on other sites
porschpow 7 #20 Posted June 22, 2021 Ok, good to know! I am assuming the one that hooks into the seat switch is most likely bypassed. I will trace the wiring to see which switch goes to the starter. Share this post Link to post Share on other sites
lynnmor 6,698 #21 Posted June 22, 2021 29 minutes ago, Handy Don said: Great! One switch locks out the starter. The other kills the engine if the operator isn't in the seat. There is only one switch on most 520H tractors, I'm not even trying to determine the model year discussed here. Share this post Link to post Share on other sites
Handy Don 10,439 #22 Posted June 22, 2021 I'm a broken record on this, but here goes: please repair broken or non-functional safety switches, remove any bypasses, and do not add any bypasses. It takes only a moment's inattention or a brief distraction to inflict a serious injury on oneself or others. These machines are powerful. One member called the deck the Three Blades of Doom. On some later 520's there is single PTO switch that operates a DPDT relay that then interacts with the seat switch/ignition and the neutral/starter circuits. On earlier models, there are two separate PTO switches for the two circuits. On the latter (like mine), the wiring looks like this: Share this post Link to post Share on other sites
porschpow 7 #23 Posted July 20, 2021 Thanks a lot for all your help folks! As it turns out, when jiggling the pto leaver down a third of the way, the it turns over. I am goign to tear into it when I get a free chance. In the mean time, I will have to jiggle (if need be) Share this post Link to post Share on other sites
Handy Don 10,439 #24 Posted July 20, 2021 As you get into PTO lever and switches, you can pay attention to where it has more play or other issues than it should. @peter lena did a thread on refurbishing his--use all or part of what he did! Check back here as you go and share some pictures of you work. Best of luck! 1 Share this post Link to post Share on other sites
porschpow 7 #25 Posted July 21, 2021 Thanks so much! Share this post Link to post Share on other sites