520-8

[dkg520 510]

I have a 520-8 that was running great til last week.  I turn the key and get no power at all.  New battery installed and I have power to the starter but nothing when I turn the key.  I tried a new ignition switch but get the same result.  Anyone have any ideas on where I should start. Thanks for any help.

[gwest_ca-(File Mod) 11,102]

Download this file. Each circuit has it's own diagram making it easy to follow. They illustrate what it takes to make it work.

 

[Handy Don 12,472]

32 minutes ago, dkg520 said:

Anyone have any ideas on where I should start. Thanks for any help.

I always start with obvious connections--are they clean and tight?

Battery positive and negative?

Ground from battery to engine?

Connections to the ignition switch?

Connections to safety switches?

And, specific to the Onan-powered tractors, any visible damage or overheat evidence at the 9-pin connector that links the engine wiring to the tractor?

 

Then look for broken or frayed wires.

 

I’m not directly familiar with that model, but in your situation, “no life when trying the key”, I’d look for problems at the safety switches--disconnected wires or broken switches, for example. Clutch, seat, and PTO safeties can all affect start/run. Use the wiring guide to look for continuity and voltages as you trace the wires. I’m assuming you have a working volt/ohm meter and know how to use it, of course!

 

Take NOTHING for granted -- I even, sometimes, distrust a new battery until I’ve tested it.

[ri702bill 8,513]

Onan engine with the dreaded 9 pin Connector?? If so, there's a good place to look for apparent issues.....

[Ed Kennell 38,688]

52 minutes ago, dkg520 said:

I have power to the starter

If you have 12v to the starter it should be spinning.    If it is spinning and not engaging the flywheel, you need to clean the bendix.

[lynnmor 7,354]

You will have power at the big wire at the starter, check for power at the small blue wire when you turn the key to start. 

[Handy Don 12,472]

Sorry, this may be plug simple and I missed it.

Is the PTO disengaged? If not, no start!

(No need to ask how I know about this.)

[SylvanLakeWH 25,977]

6 minutes ago, Handy Don said:

Sorry, this may be plug simple and I missed it.

Is the PTO disengaged? If not, no start!

(No need to ask how I know about this.)

 

I've heard that some people may have, uhm, done that... 

[Ed Kennell 38,688]

Just now, SylvanLakeWH said:

 

I've heard that some people may have, uhm, done that... 

   Usually when you run out of fuel while mowing.   Carry fuel out and fill the tank and no start.    

[8ntruck 7,102]

3 hours ago, SylvanLakeWH said:

 

I've heard that some people may have, uhm, done that... 

Nope.  Not me.  Never ever.

[953 nut 55,858]

There is a 25 amp fuse in line from the battery (via the solenoid connection) to the ignition switch. It is near the battery and over the years acid fumes from the battery being charged will cause the fuse holder to begin corroding. This is likely to be the problem, replace it with a HEAVY DUTY 30 amp fuse holder.

[dkg520 510]

Spent all morning checking and tightening all connections but still nothing at all when I turn the key.  Can anyone tell me what this is?  And what it does.  Thanks

[Handy Don 12,472]

Yes. It is a relay.

Apply 12v power across terminals 1 & 2 and it closes the circuit across terminals 3 and 5.

 

From the schematic, it looks like the Start Relay.

If it is:

- the red wire should go to a terminal on the starter motor that also has a wire from the battery

- and a light blue wire should go to a different terminal on the starter motor. 

 

As I read the diagram, a test jumper between the these two would circumvent ALL safety switches and most other wiring and crank the engine (BE SURE THE TRACTOR IS IN NEUTRAL WITH THE PARKING BRAKE SET BEFORE ATTEMPTING THIS). If this works the problem is at or before the relay.

 

With the relay in place, can you jumper 12v from the battery + into the socket where the light blue wire from the clutch pedal enters? This tests the relay by circumventing the fuse, the ignition switch, and the PTO and clutch safety switches. to trigger the relay and cause the tractor to crank. If yes, the relay is good and the problem is before the relay.

 

PTO is disengaged?

Clutch pedal is down?

If you disconnect the relay (remove it from the socket), an attempt to start (with the above conditions met) should get you 12volts in the socket where the light blue wire enters on either terminal 1 or 2 (it’ll be coming from the clutch pedal switch). If not, you know the problem is in the fuse, the ignition switch, or the PTO or clutch pedal safety switches. Work backward looking for the 12v.

 

Let us know what you find.

[dkg520 510]

Where exactly will I find the clutch pedal switch?  Thank you for you help

[Ed Kennell 38,688]

13 minutes ago, dkg520 said:

Where exactly will I find the clutch pedal switch?  Thank you for you help

The inner side of the clutch pedal contacts the switch when the pedal is depressed.

[Handy Don 12,472]

37 minutes ago, dkg520 said:

Where exactly will I find the clutch pedal switch?  Thank you for you help

That I don’t know--not a model I’ve worked on.

 

Not being cheeky, I’d trace that light blue wire that DOESN’t go to the starter. It should lead to the clutch switch which must be near the pedal or linkage so that it can detect when the pedal is depressed.

I assume you have the manual with the IPL (illustrated part list). If not, search in the Files section of this site for “Tractor 1990 520-8 IPL” (set the “use all search terms” option). That’ll help you locate the manual which might help--at least it’ll show you what the switch looks like!

[dkg520 510]

Thank you all

[gwest_ca-(File Mod) 11,102]

I believe the clutch switch is item 60 at the bottom right of this page.

https://www.partstree.com/models/41-20o801-520-8-toro-garden-tractor-1990/electrical-system-11/

I think you will find it between the transmission drive belt idler pully and the center consul. It is on the inside and the top/back of it can be seen if you look through the shifter slots in the panel.

This is based on what other 1990 models used although the 520-8 switch 119440 is different for some reason.

[dkg520 510]

Thanks. I was all over my 520-8 today and didn’t see anything at all like item 60?  I have the center console out and I have item 41 but it not plugged into anything?  Should item 60 be in the center console or behind a guard somewhere?

[RJ Hamner 1,011]

Item 60 should be on the right side and the tension arm for the clutch activates it when the clutch pedal is depressed. (safety switch) clutch must be depressed to start

Item 41 is the switch on the seat.  It activates when your butt is in the seat. lt may or may not have a  wire loop inserted to bypass the switch ( of course I would never bypass a safety switch)

 

hope that helps

 

Bob

[dkg520 510]

Yes it does

[dkg520 510]

Well guys let me start by thanking everyone for their help with my problem.  Today I tracked the problem down to the 9 pin connector.  I took it apart to look for any signs of heat or burning but when I put it back together the machine started and ran perfect.  I’m still not quite sure what the permanent fix for the problem is but it’s running again.  Thank you all

[Handy Don 12,472]

13 minutes ago, dkg520 said:

Well guys let me start by thanking everyone for their help with my problem.  Today I tracked the problem down to the 9 pin connector.  I took it apart to look for any signs of heat or burning but when I put it back together the machine started and ran perfect.  I’m still not quite sure what the permanent fix for the problem is but it’s running again.  Thank you all

Great news!

Guys have taken a couple of approaches to balky 9-pins: a replacement connector (available from Wheel Horse Parts and More, a vendor here), or new, waterproof 2- and 3-conductor connectors. Not all 9 pins are used in the existing connector.

That connector was a significant expedient for WH during manufacture when connecting the engine to the tractor but that type is vulnerable to moisture and corrosion.  

[953 nut 55,858]

19 hours ago, dkg520 said:

Well guys let me start by thanking everyone for their help with my problem.  Today I tracked the problem down to the 9 pin connector.  I took it apart to look for any signs of heat or burning but when I put it back together the machine started and ran perfect.  I’m still not quite sure what the permanent fix for the problem is but it’s running again.  Thank you all

The 9 pin lives near the battery and is subject to a bit of acid fumes as the battery charges. By unplugging and reconnecting the plug you apparently scraped enough corrosion off to make a good enough electrical connection to allow the solenoid to work. I would suggest cleaning it up the best you can and sealing it with some dielectric grease.

Edited December 6 by 953 nut
Spell correct put in the wrong word !

[Ed Kennell 38,688]

5 minutes ago, 953 nut said:

. By unplugging and reconnecting the plug you apparently scraped enough corrosion off to make a good enough electrical commotion 

Just a good regular maintenance practice to disconnect and reconnect all connectors several times to clean and reestablish good contact.

Many of these connectors are dissimilar metals that corrode quickly.   This was the case in a new Jeep Wagoneer that I bought many years ago.   It had a habit of just shutting down usually when I was rolling down the 4 lane at 70MPH.   Quite exciting when you lose power to the brakes and steering.  I found the problem by jiggling the connector, cut it out and never had a problem again.   About 6 months later I received a recall from Jeep  to remove the connector.