1982 John Deere 108 Lawn Tractor PTO Problems

[SHOOTERTPP]

I'm working on a 108 lawn tractor for a rancher friend of mine from out in west Texas.

Long story about how I came to be working on it, but so far I have replace the starter ( someone put the wrong one on it), replaced the flywheel (due to wrong starter), replace the point and condenser system with the magnetron system and rebuilt the carburetor. Now that it is running well, it was time to check out the rest of it.

The next problem I am now encountering is that when I engage the PTO by flipping the switch on the dash, the motor immediately dies.

I have disconnected the PTO clutch at the connector on the frame down by the clutch, but it still dies when the switch is flipped to the on position.

Here is the PTO switch.

Using a VOM, when the switch is in the off position, there is continuity between the center post and the upper right. Nothing else.

When the switch is on, there is continuity between the lower right and center and also between the two post on the left. The two circuits seem to be separate and do not appear to have any relationship to each other.

Anyone have a wiring schematic?

Any ideas where to go from here?

 

[meck]

I am having the same problem...If I find a solution I will let you know

 

[SHOOTERTPP]

I will as well.

I am tracking down a new pto switch as I type.

The switch is the main reason I'm working on this in the first place.
When this all started about a year ago, it would not crank at all. The owner bought and replaced the key switch but it still wouldn't crank.

I looked at it and tested the circuits and determined the pto switch was the culprit. Only after moving the switch back and forth very fast about 20 times did it make the connection inside the switch to allow the engine to start.

 

[SHOOTERTPP]

Problem solved:

It turns out that who ever had been working on it before had disconnected the seat safety switch and had taken the white wire out of the wire loom that had went to the switch and grounded it to the frame of the tractor.

The seat safety switch actually grounds the white wire when no one is sitting in the seat there by killing the engine, just like turning off the key.

I disconnected the white wire from where they had grounded it and when the switch is flipped to the on position it didn't die. I then reconnected the PTO under the frame and it came on and the engine continued to run. I then put the belt back on the pulley and again started it an energized the circuit and the PTO engaged and the blades turned.

Meck.... I would look at the safety switch under the seat. Maybe it is defective and not opening up when you sit in the seat.

 

[meck]

Shooter,
I disconnected the safety switch from underneath the seat awhile ago and it ran fine, what I did with the pto switch was taken the 2 wire plug off and cranked it over and it started,
then I hit the PTO switch on and the blades turned, I hooked up the plug again with the blades running and everything works fine now...lol so you tell me. These JD's can be frustrating and a pain in the butt sometimes but it beats walking the lawn.
Thank you for repying to my post