72 gt 14 pto clutch

[jgrammer243 16]

Ive got a 72 gt14 with an electric clutch that i cant seem to get engaged. just recently acquired the tractor and previous owner had the clutch apart with a break in the wiring. I ordered a new (used) clutch from az tractors on here. I have voltage coming to the clutch (14V) and continuity through the clutch itself. What am i missing here? any help is appreciated thanks!

 

72 gt 14 

1 0502 7

897061

[pfrederi 17,642]

In addition to continuity through the coil check for resistance.  Do you hear a loud click when you apply voltage?  Do you see any movement when you engage it?

[jgrammer243 16]

I have a reading of 3.0 ohms with the clutch coil and 14V at the plug when the pto switch is engaged. I dont see any movement at all nor do i hear a click but its also fairly loud

Edited May 21, 2017 by jgrammer243

[pfrederi 17,642]

Try the clutch with the engine not running...Ignition switch in the run position.

 

There is not much movement The disk highlighted in yellow should move towards the coil assembly (direction of arrow) only moves about an 1/8 of an inch.

 

The gap between the yellow disk and the coil assembly when the PTO is off is called air gap.  Wheel Horse doesn't much mention it in its manuals.  When JD uses electric PTOs they make a big deal about adjusting the air gap....go figure.

 

 

Edited May 21, 2017 by pfrederi

[jgrammer243 16]

with the engine off, switch in run. i engage the pto switch and i have nothing. no movement, no sound

[953 nut 55,025]

I think the ignition switch on your GT-14 may have two RUN positions. When you start the tractor it will spring return to RUN and if you turn it counterclockwise one click it will be in the RUN-ACCESSORY position and that will send power to the PTO clutch.

[953 nut 55,025]

Also there should be a fuse in line.

[jgrammer243 16]

The ignition switch is Off, Run, and Crank which is spring loaded back to run. also, there is no fuse in line with the Pto. I have 14V when engaged. clutch coil resistance is 3 ohms. not sure where else to go other than checking the air gap previously stated above

[6bg6ga 272]

17 hours ago, pfrederi said:

In addition to continuity through the coil check for resistance.  Do you hear a loud click when you apply voltage?  Do you see any movement when you engage it?

 

Good advice. I will inject one thing. When trying to check resistance this low it is important that one knows how accurate their meter is. I suggest that one purchase a quality 1% resistor of 2 or 3 ohms. Check the resistor with your meter and note the reading. Most if not all meters are off and knowing how far off your meter is important in your troubleshooting ability.

[jgrammer243 16]

i do have a Fluke multimeter, calibrated by Fluke just a few months ago 

[pfrederi 17,642]

This is a bit of a puzzlement.....Look at the thin gap just to the right of the highlighted disk (the gap the arrow points to).  How big is your gap???

[gwest_ca-(File Mod) 11,029]

Some of the later models came with a separate manual with setup instructions for the servicing dealer. This is from one of them 1998 267-H but theory should be the same. I don't know if the older models even had a method of adjustment but have seen where a too wide of gap on the later models would not apply the clutch. Magnetism must have been too weak with the wider gap.

 

Garry

[pfrederi 17,642]

Garry you are the man when it comes to finding good stuff.  This is the kind of detail John Deere has on Electric PTOs. Unfortunately the adjustment process for the older units is pretty blunt.  You bend three metal tabs the thin metal pieces in the bottom half of the units pictured.....  I haven't seen a spec for the airgap on the older units.  i have two horses with working PTOs so i am off to the storage shed to measure the gap and see what a working system has.

 

 

Edit:   Went up and measured the air gap on the two horses (Charger /Electro)that use electric PTOs  One measured .038 the other .030 they both work.

 

 Another test with engine off but PTO turned on see if the face of the PTO attracts steel.  Mine both ant e to pull on the feeler gauge  held up against the front of the PTO.  If you have that magnetism then we have to look at the air gap or something (corrosion) keeping it from moving.

 

 

Edited May 22, 2017 by pfrederi

[jgrammer243 16]

Correction- with the engine off, switch in run. I only have 5.5 or so volts coming to the pto clutch where i think i need about 8 or so...i have 12.3 volts at the pto switch. am i losing too much voltage through the switch and it needs replaced as well? Thank you guys for all your help

[pfrederi 17,642]

1 hour ago, jgrammer243 said:

Correction- with the engine off, switch in run. I only have 5.5 or so volts coming to the pto clutch where i think i need about 8 or so...i have 12.3 volts at the pto switch. am i losing too much voltage through the switch and it needs replaced as well? Thank you guys for all your help

Jump a wire from you r battery + terminal to the PTO.  If it snaps then you have a switch/wire problem

 

Incidentally 12.3 is kind of low at the switch.  Engine off good battery should be 12.6

Edited May 22, 2017 by pfrederi

[jgrammer243 16]

11 hours ago, pfrederi said:

Jump a wire from you r battery + terminal to the PTO.  If it snaps then you have a switch/wire problem

 

Incidentally 12.3 is kind of low at the switch.  Engine off good battery should be 12.6

thanks! will try that as soon as i'm off today. does anyone make new switches that will fit and look original?

[6bg6ga 272]

Again without checking your meter with a reliable one the voltage reading is just as much of a guess as the ohms scale. One meter may register a 12.3 another may show a 12.6 off the same battery. I have a half dozen meters at home in the garage and every one will show a little different reading. I would not judge a 12.3 reading as a low reading. Does it start ok? If not then question the battery and have it checked with a calibrated meter, until then don't put too much weight on a .3 of a volt difference. I recently had a battery that measured a straight 12 volts and it lasted three years after I had questioned its life.

[jgrammer243 16]

Battery is ok. it doesn't have a problem starting ever. I have a Fluke multimeter just calibrated maybe two months ago so i know i'm good there. I have 12v to the hot side of the pto switch. when i engage it, only 5.5 or so volts come out going to the clutch. I couldn't wait this morning and ended up jumper wiring from battery positive straight to the clutch and WE HAVE MOVEMENT! gonna go with i need me a new switch! just very confusing when i had 14 volts coming to the clutch while the engine was running. Electrical..😤 Does anyone know of a new switch that will exactly fit or do i need to look used? thank you all! 

[pfrederi 17,642]

19 minutes ago, jgrammer243 said:

Battery is ok. it doesn't have a problem starting ever. I have a Fluke multimeter just calibrated maybe two months ago so i know i'm good there. I have 12v to the hot side of the pto switch. when i engage it, only 5.5 or so volts come out going to the clutch. I couldn't wait this morning and ended up jumper wiring from battery positive straight to the clutch and WE HAVE MOVEMENT! gonna go with i need me a new switch! just very confusing when i had 14 volts coming to the clutch while the engine was running. Electrical..😤 Does anyone know of a new switch that will exactly fit or do i need to look used? thank you all! 

That is great news!!!  Sorry I don't have  a GT so i don't know what an appropriate switch would be.  FYI based on watching the ammeter on my two Horses with Electric PTO they draw about 6 amps engaged.  There may be a surge as they turn on but I don't see it on the units ammeter.

I am not an electrician but maybe you had 14 volts running but not enough amperage to work it????

Edited May 23, 2017 by pfrederi

[6bg6ga 272]

8 hours ago, jgrammer243 said:

Battery is ok. it doesn't have a problem starting ever. I have a Fluke multimeter just calibrated maybe two months ago so i know i'm good there. I have 12v to the hot side of the pto switch. when i engage it, only 5.5 or so volts come out going to the clutch. I couldn't wait this morning and ended up jumper wiring from battery positive straight to the clutch and WE HAVE MOVEMENT! gonna go with i need me a new switch! just very confusing when i had 14 volts coming to the clutch while the engine was running. Electrical..😤 Does anyone know of a new switch that will exactly fit or do i need to look used? thank you all! 

 

Before you purchase a thing un-terminate the circuit from the battery and measure the resistance thru the wire and thru wire AND the switch. I would suspect the wiring has resistance. You don't have anything to loose except a few minutes of your time. Generally a switch either works or it doesn't. What is the correct gauge of wire per the factory schematic? Has your been changed?

 

 

[gwest_ca-(File Mod) 11,029]

The parts list available from Toro for the 1972 GT-14 show the pto switch as 100769.

We do have an original 1971 parts list which I have more faith in and it lists the same switch for the 1971 GT-14.

The switch is no longer available from Toro but Toro and Wheel Horse did not make switches. They sourced them from somewhere.

I don't know what they are like so maybe a good description of what you have can be confirmed by other GT-14 owners. A good photo would be better.

 

Garry

[6bg6ga 272]

Want to make it work for years?  Here is my suggestion.  First with the switch disconnected from the circuit check it using the ohms scale. If the resistance reads 0 ohms or near zero ohms use it to trigger a relay. The relay would be something like a NTE R51-5D40-12F50A and the price is $7.25 plus shipping.  Use the switch if good to turn the relay on. You will simply need to add a length of wire to the relay and from the relay to the PTO.