1862 cub checking seat switches

[Mr Bob]

Needing Help. 6" pto will only run if pto switch is held up in start position. The minute you release pto switch, pto stops. I have read much about this and most members say to check the seat switches. I really don't know how to check them. I took the seat off, took both wiring harnesses off. Using my digital meter I checked the oms on each. The switch with the yellow and orange wires gave me no reading. The wiring diagram shows N/C. I got a reading on the switch with a black and a violet wire. The electrical diagram says N/O. Is this telling me anything? Also a prong on the switch with the yellow and orange wires has a very loose prong. I don't know how to check for voltage in the harnesses that hook to the switches. Any help will be appreciated. Thanks in advance and have a great day.
Bob

[West Valley G]

Hi Bob, sounds like a pretty good description of a seat switch issue.
I would think you could not worry about the voltage at those switches
but check them for continuity to figure out what is going on.
The one that is NC should give you continuity until you depress the
switch, then the circuit should break. The NO switch should give you nothing
till you engage the switch, then you should have a closed circuit.
I hope I don't have that backwards? If I do, do the opposite.

Don't know if I am allowed to say this but. With both switches manually
depressed your PTO should engage if that is the problem..

Ken

[Frank1541]

You have it right.
NC stands for Normally Closed contacts
NO stands for Normally Open contacts. This is the one that affects the PTO. (The NC switch is for the engine kill circuit).
The most likely culprit is the PTO switch itself. Contacts 3 and 4 need to be connected together for the PTO to run after PTO start.

[spndncash]

the wiring diagrams is in this link (among others). I found their library is quite useful.
https://pandpsmallengines.com/pages/...arden-tractors
looks like the seat switch for PTO is NO and the one for the ignition is NC
the reverse switch/relay is in there as well as the brake switch.

If I remember right the sequence is the PTO will stay on if the brake is engaged and you get off the seat. but without the brake engaged if you get off the seat the PTO cuts out and needs to be turned back on. if you reverse the PTO might cut out as well but does not need to be reset - but I may be confusing that with JD's sequence.

[Mr Bob]

Thank all of you that responded.
Ken, I checked the continuity on both switches. These switches are activated by current passing through them. The NC switch did not register any ohms when checked. The NO switch registered ohms when checked. It seems this is reversed from what you said. I would like to bypass the switch that affects the PTO. Can I do this by connecting a wire to each wire going to the switch? One end to each wire. Thanks so much for every ones help and have a great day.
Bob

[spndncash]

the NC switch can be bypassed with a wire. please be careful as this will defeat the safety mechanism of shutting off the pto and mower deck when you are not in the seat.
that said mine has been bypassed for 20 plus years

[West Valley G]

It would seem that if the NO switch has continuity when you engage it
then that would not be the problem?
You could certainly go around it as you described.
Sounds like Frank has the next thing to check in his post.

Ken

[darkminion_17]

The air gap may need to be adjusted on the PTO, did you try that first?

[Mr Bob]

Hi darkminon 17. I did try to check the gap but with this 6" PTO I was unable to get the feeler gauge in at all 3 places. Not enough room to get a straight angle to check. With the PTO running with the PTO switch held up in the start position, wouldn't that eliminate the air gap issue? Thanks for replying and have a great day.
Bob

[darkminion_17]

Doing that will most likely burn out the reverse relay, or melt some wires at their connection points.

wiring diagram for pto