John Deere z737 stopped mowing

[DeputyDawg]

I was mowing with my John Deere z737 when the mower deck quit turning. I stopped, pushed in the PTO Switch, turned off the mower, got off and checked all the belts which were ok, checked if blades were frozen and they were not. Then I started the mower and drove to the barn. After checking everything and finding nothing visible I tried to start the mower again. It would not start. All the handles were in the right position. I checked the battery and had 12.5v. There is no click when I try to start it. The oil and battery light are visible as is the hours meter. It is a great mower and I've never had any trouble with it. Has around 270 hours on it.

So my questions are:
What would make the mower stop working while mowing?
Why wouldn’t I be able to start it again?
Are the two events connected?

 

[mechanic mark]

Check all wiring & connections by hand ensuring everything is tight & secure, especially ground cables & straps from engine to chassis.

 

[bertsmobile1]

You can read and print out sections of the JD owners manual from here
http://manuals.deere.com/cceomview/OMTCU15013_L1/Output/OMTCU15013_L118.html
JD also do an excellent service manual for your mower that will pay for itself the first time you use it.

From what you say sounds like a safety switch or relay has packed it in

 

[DeputyDawg]

I checked all of the connections.

I even replaced the seat switch.

When I turn it on I get the 2 lights and it shows the hours and when I turn the switch on it just clicks once.

I even turned the PTO on and when switch turned there is no click (as expected).

I checked the fuse and it is ok.

I even tried jumping it in case the battery which gave me 12+v was incorrect.

Suggestions? Grass is growing!!

Thanks.

 

[mechanic mark]

http://www.greenpartstore.com/Model-737_c_326-1-3.html

unplug connections one at a time & inspect both male & female plugs for dirt, corrosion, etc., clean connections, pick up a tube of "dielectric tune up grease" from your local auto parts store & apply to all plug connections. let us know how it goes.

 

[DeputyDawg]

Here is what I did.

I cleaned out with electrical cleaner spray the connections at the seat, both levers, the brake and the one by the spark plug.

Here are my readings.

Battery with key off..12.2v
Battery with key on..12.1v
With key on voltage at seat..0.9v
With key on voltage at Break..11.9v
With key on voltage at Handles..0.1 and 2
With key on voltage at Connector by spark plug..12.2v

Rechecked the fuse in front of the seat and okay. Are there any other fuses?

I checked the connector at the switch and PTO and they were snug.

I put on a new switch at the seat with no difference.

Do you think I need the battery load tested?

Suggestions?

Thanks.

 

[bertsmobile1]

Yes the battery voltage is low.
Cheap and nasty test is to remove the ground terminal from the battery then run a jumper from the starter + to the battery.
Run another jumper from a good grounding point close to the starter and bring it around to the battery.
You should get a healthy spark when you connect the ground jumper to the battery and the starter should crank if the stater & the battery are both good.

 

[DeputyDawg]

I checked it again and had 12.3v on the battery at off, on, and start.

I pulled, cleaned, and checked the ignition switch and the continuity all checked out okay as described by many posts on You Tube and the net.

I pulled the PTO Switch off and I don't know what's good or bad.

_____1 _______2

______3 ______4 _______5

In checking PTO Switch for continuity the above diagram shows the post on the switch

When switch is OFF
Post 1 and 2 - I get tone
Post 3 and 5 - I get tone
I get nothing when touching Post 4 to 3 or 5

When switch is ON
I only get a tone when I touch Posts 3 and 4
Any other combination there is no tone

So is the PTO Switch good or bad?

 

[bertsmobile1]

In the cranking circuit power goes from the battery via the fuse to the B terminal on the ignition switch.
From there it exits via the the S terminal on the ignition switch to the PTO switch where it passes through only when the PTO is off.
From the PTO on most ZTR's it goes to the + trigger of a relay.
The parking brake and lap bar switches are grounded and pass on this ground to the ground trigger terminal on the same relay.
This relay then passes a + feed to the starter solenoid which trips if it is also grounded and passes high current battery power to the starter.

On some ZTR's that do not use cranking relays, the + from the PTO will go directly to the starter solenoid + terminal while the - ( ground ) will go directly to the ground terminal on the starter solenoid.

I am yet to have a 737 in the work shop so I have no need to fork out the money for the JD service manual specific to that model.
However all mowers are basically wired the same way.

measuring continuity should be done whey you need to verify continuity.
Measuring for voltage should be done when you need to verify voltage.
The two are not the same.
If you are getting a 12.5 V reading then you MUST have continuity but rust or dust will give a continuity reading but not carry voltage.

Most starter solenoids need 10V minimum to trip ( this protects the starter motor )
Most PTO clutches need 8 V or better to trip , this protects the winding in the clutch.

 

[DeputyDawg]

Well, I found one broken wire by the starter and after I repaired it the mower started and I went and mowed for about 10 minutes before the mower stopped working. So now it runs but the PTO will not engage. When I have the mower running and pull the PTO the orange light (battery I think) gets dimmer. My shade tree assessment is there is another short in one of the lines. But I'm open to suggestions. Does anyone know what color the PTO lines would be and the routing? Everything runs into a harness. I thought the PTO switch might be bad but it did work for a little bit. The continuity check seams to be okay on the switch.