1975 C160 Auto

[Krice58 23]

Between my vacuum evacuator, pulling the plug and filter off, I got a little under 4 quarts of oil out. Total capacity is 6, but I know with the lines and everything it’s not completely empty and it was low to begin with. So I guess put 4 back in and slowly fill and check until full? It’s not currently running as I’m waiting on parts, will that matter as I will not be able to cycle the system? 

[Ed Kennell 42,170]

To test a hydro in a non runner, I often park a running tractor behind and drive the non runner hydro from the PTO of the runner.    I have the non runner strapped to a tree and test the hydro to spin the tires in forward and reverse.    If the hydro does not test strong, it usually becomes a parts tractor.

[953 nut 60,348]

4 hours ago, Krice58 said:

So I guess put 4 back in and slowly fill and check until full

It helps to have a piece of wire alongside the funnel to maintain a vent path while filling, that will prevent burping and splashing back. Some people use a dinking straw going through the funnel as a vent.

[mrc 960]

there is a hump in the bottom of the tranny casting.   obviously remove drain plug and let it drain till it drips.   then jack up the front of the tractor as high as you can.   you will be surprised how much more oil will drain out.   after refilling, drive it forward and reverse and cycle the lift lever multiple times.   then recheck your dipstick.  it will probably need topping off.

[Krice58 23]

Starting wiring using a few diagrams I found, and I’m just a bit confused. Everything is pretty straight forward except for the pto safety switch and seat switch. The pto switch is four terminal, but had like six wires going to it. I’m trying to figure out which pin corresponds to what as I don’t see any markings. 

[953 nut 60,348]

The 1975 drawing should help clarify the PTO wiring. It has two drawings of the PTO switch, one with it ON and one with it OFF. 

Both halves of the PTO switch are normally open (NO). With the PTO in the OFF position the lever will apply pressure to the switch closing both pairs of contacts. With the PTO in the OFF position power will go to the ignition coil with the ignition switch in the run position. Also, power will go to the starter solenoid (via the brake switch) when the ignition switch is in the start position. With the PTO in the ON position both switches will open preventing the starter from operating and interupting the power to the ignition coil unless the seat switch is depressed. With a driver in the seat the ignition will continue to operate with the PTO on.

Using an ohm meter you will find that two pairs of the PTO switch terminals will show continuity with the switch activated (pressure applied) and both of these pairs will  have no continuity when pressure is released from the switch. It is not important which function is on a particular pair of terminals.

The seat switch is also a NO (normally Open) switch and will be close when a driver is in the seat.

[Krice58 23]

Anyone one have a part # for the toggle switch on the dash for the electric pto clutch? Looks like a 4 terminal, but there was an aftermarket two terminal on mine that is rusted away. 

Edited August 8 by Krice58

[Krice58 23]

Well I’ve got the wiring pretty much complete, and no dice. It will not crank from the key switch but with turn over if I jump the solenoid. I think I just have a poor connection going to the brake switch. When I was tearing things apart I noticed someone did bypass the seat switch, and I wired it back in, how likely is it that it failed? There must’ve been a reason it was bypassed. I did replace all of the ignition parts, however not 100% sure I got the timing correct, so I’ll have to check that. I assume if that’s off, it wouldn’t run either. Any tips for timing would be appreciated. It’s the K341 16 horse. 

[953 nut 60,348]

23 hours ago, Krice58 said:

It will not crank from the key switch but with turn over if I jump the solenoid.

With the transmission in neutral and the wheels blocked use a small jumper wire from the battery + terminal to the small solenoid terminal that has a wire going to the brake switch. If the solenoid closes then the wire to or from the brake switch is likely to be the problem. If it doesn't close then the solenoid or its ground would be the problem.

[Krice58 23]

On 8/11/2025 at 7:25 PM, 953 nut said:

With the transmission in neutral and the wheels blocked use a small jumper wire from the battery + terminal to the small solenoid terminal that has a wire going to the brake switch. If the solenoid closes then the wire to or from the brake switch is likely to be the problem. If it doesn't close then the solenoid or its ground would be the problem.

I’ve confirmed the brake switch does work, the problem I’m running into now is related to the pto switch. Every time the key switch is in the on position the engine will crank if the pto is off, if I engage the pto it cranks normally, but it doesn’t want to fire either way. It did start briefly, so I believe that’s just a dirty carb issue, which I expected. I’m lost, I apologize, wiring isn’t my strong suit. 

[gwest_ca-(File Mod) 11,522]

There is a photo of the switch connector and the wires in this file. Wire colors may not match as this switch was used for multiple years.

Click on the picture

 

[gwest_ca-(File Mod) 11,522]

On 8/7/2025 at 2:02 PM, Krice58 said:

Anyone one have a part # for the toggle switch on the dash for the electric pto clutch? Looks like a 4 terminal, but there was an aftermarket two terminal on mine that is rusted away. 

May be this switch but do you need it? It also controlled the starter like the manual pto switch. You can not use both. Click on the picture for more.

 

[Krice58 23]

1 minute ago, gwest_ca said:

May be this switch but do you need it? It also controlled the starter like the manual pto switch. You can not use both. Click on the picture for more.

 

I don’t actually think it was originally equipped with this switch. I think it was just an extra accessory switch someone put in the dash because it does not have an electric pto clutch. I took that one out completely. Just have the ignition switch and light switch. 

[gwest_ca-(File Mod) 11,522]

OK I see now.

There was a kit back in the day to install an electric clutch listed for this model of tractor. Kit number 8-3513 or 83513.

 

[953 nut 60,348]

11 hours ago, Krice58 said:

Every time the key switch is in the on position the engine will crank if the pto is off, if I engage the pto it cranks normally, but it doesn’t want to fire either way. It did start briefly, so I believe that’s just a dirty carb issue, once we get your wiring problem out of the way we can work on the fuel system. which I expected. I’m lost, I apologize, wiring isn’t my strong suit. 

No need to apologize, most people are electrically challenged.

Your PTO switch has two parts (two switches in one housing) and we just need to get the wires on the correct terminals so it will do its job. 

 

Six wires are attached to the PTO switch. I won’t go into too much theory on how the switches interact, just get your wires hooked up so you can get things working properly.

Two of those wires come from your seat switch, both are black and they need to be separated from one another. There is also a black wire coming from your ignition switch “I” terminal and a black wire going to your ignition coil + terminal. One wire from the seat switch will be paired with the wire coming from the ignition switch and the other wire from the seat switch will be paired with the wire going to the ignition coil. Once these two pairs of wires have been joined we will consider each pair to be one black wire pair.

There are two RED wires going to the PTO switch.  One red wire comes from the ignition switch S terminal and the other goes to the brake/clutch switch and on down to the solenoid.

With the switch sitting on the table and no force applied use a multimeter to check for continuity between the four terminals, there should be no continuity. Now push and hold the button and check for continuity. There should be two pairs of terminals that have continuity and neither pair should have continuity to the other.

Mark the two switch pairs that have continuity, call one pair RED and the other pair BLACK.

Disconnect the battery prior to attaching any wires to the switch.

Attach one black wire pair to one of the black switch terminals and connect the other black wire pair to the other black switch terminal.

Attach one red wire to one of the red switch terminals and attach the other red wire to the other red switch terminal.

Connect the battery, turn the key to start, and your starter should work properly with the PTO off and not work with the PTO on. Likewise, there should be 12 volts to the ignition coil with the ignition switch in the run position and the PTO off. With a driver in the seat the 12 volts to the coil should remain with the PTO on until the driver leaves the seat.

[Krice58 23]

4 hours ago, 953 nut said:

No need to apologize, most people are electrically challenged.

Your PTO switch has two parts (two switches in one housing) and we just need to get the wires on the correct terminals so it will do its job. 

 

Six wires are attached to the PTO switch. I won’t go into too much theory on how the switches interact, just get your wires hooked up so you can get things working properly.

Two of those wires come from your seat switch, both are black and they need to be separated from one another. There is also a black wire coming from your ignition switch “I” terminal and a black wire going to your ignition coil + terminal. One wire from the seat switch will be paired with the wire coming from the ignition switch and the other wire from the seat switch will be paired with the wire going to the ignition coil. Once these two pairs of wires have been joined we will consider each pair to be one black wire pair.

There are two RED wires going to the PTO switch.  One red wire comes from the ignition switch S terminal and the other goes to the brake/clutch switch and on down to the solenoid.

With the switch sitting on the table and no force applied use a multimeter to check for continuity between the four terminals, there should be no continuity. Now push and hold the button and check for continuity. There should be two pairs of terminals that have continuity and neither pair should have continuity to the other.

Mark the two switch pairs that have continuity, call one pair RED and the other pair BLACK.

Disconnect the battery prior to attaching any wires to the switch.

Attach one black wire pair to one of the black switch terminals and connect the other black wire pair to the other black switch terminal.

Attach one red wire to one of the red switch terminals and attach the other red wire to the other red switch terminal.

Connect the battery, turn the key to start, and your starter should work properly with the PTO off and not work with the PTO on. Likewise, there should be 12 volts to the ignition coil with the ignition switch in the run position and the PTO off. With a driver in the seat the 12 volts to the coil should remain with the PTO on until the driver leaves the seat.

Awesome. This worked! Thank you. Now my wiring is sorted (I think). Now onto fuel. Even with starting fluid it doesn’t want to fire. I guess next step is removing the carb and cleaning? 

Edited August 13 by Krice58

[nylyon-(Admin) 8,000]

If it won’t fire with starting fluid, I would look towards spark and / or compression before carburator.

 

[Krice58 23]

Never mind. Now I have no spark. I am getting power to the ignition coil, but no spark whatsoever when testing. Also the wires for the rectifier and ammeter smoked and melted the plastic wire connector at the ignition switch. I tested the pto switch and the brake switch and they are both working, the seat switch is bypassed with a jumper wire for the moment. I’m at a loss. 

[nylyon-(Admin) 8,000]

If you have power to the coil, then check the points and condenser.

[953 nut 60,348]

18 hours ago, Krice58 said:

the wires for the rectifier and ammeter smoked and melted the plastic wire connector at the ignition switch.

Unfortunately the wiring used on the B and C Series didn't have fuses.  I would suspect the Amp meter has an internal short causing the meltdown. Remove the two wires from the Amp meter, bolt them together and tape over the bolt to keep it from shorting to ground. You can buy a heavy duty waterproof fuse holder and install it in the wire coming from the solenoid to the Amp meter fused at 30 Amps to protect your wiring.

18 hours ago, Krice58 said:

I have no spark. I am getting power to the ignition coil, but no spark whatsoever when testing.

Take the cover off your ignition points and clean the contacts by pulling a dollar bill or brown paper bag through the closed contacts to remove any corrosion that may be there. With the spark plug removed and key in the run position rotate the engine by hand and see if the points open and close and if a slight spark can be seen as they open.

[Krice58 23]

There was a bent connector causing the rectifier to short out to the little metal cover it mounts in. After straightening that out, no more issues with the wiring. Points and condenser are newer, no corrosion buildup. I read through a few things to check the ignition timing and it said I should have voltage to the ground side of the ignition coil after the engine completes a stroke. I have nothing, stays flat 0. I tried to do a static timing sequence and I have no changes between the contacts being opened or closed as it did in the procedure I saw. So I’m getting fuel, I’m getting power, but no spark. 

[953 nut 60,348]

Remove the wires from you ignition coil and test the primary winding and secondary windings.

 

[Krice58 23]

1 hour ago, 953 nut said:

Remove the wires from you ignition coil and test the primary winding and secondary windings.

 

Primary 3.4 ohms

 

Secondary 9300 ohms 

 

Checked the condenser too, from what I researched it said to ground it on itself check for continuity to “charge” and then voltage to “discharge”. The videos I saw showed the ohms rising as it was charging and then volts falling as it was discharged. When I replicated this, I had no rise in ohms when charging and very low volts when discharging. Could this be part of the problem? It’s a newer condenser. I wouldn’t think it failed already, but I guess it’s possible. That would cause no spark wouldn’t it?

Edited Saturday at 01:20 AM by Krice58

[953 nut 60,348]

11 hours ago, Krice58 said:

Could this be part of the problem? It’s a newer condenser. I wouldn’t think it failed already, but I guess it’s possible. That would cause no spark wouldn’t it?

A new part can be a defective part and a bad condenser will cause no spark.

Disconnect the condenser and se if the ignition system has spark. Your engine will run without a condenser, it is there to protect the points but removing it for testing won't do any harm.

[Krice58 23]

4 hours ago, 953 nut said:

A new part can be a defective part and a bad condenser will cause no spark.

Disconnect the condenser and se if the ignition system has spark. Your engine will run without a condenser, it is there to protect the points but removing it for testing won't do any harm.

No spark when doing this. Still getting ample fuel, plug is wet and carb bowl has fuel in it. 

Edited Saturday at 05:26 PM by Krice58