PTO keeps disengaging on 1772
 

Here's a new one for you guys! The PTO will disengage at random times while mowing. It will reengage, but then will disengage ever more frequently to the point that I give up and put the machine away. This actually has happened a couple of times a couple of months ago, but each time it only occurred once so didn't really think much of it, other than "maybe I knocked the switch". But now it is frequent. Is it a loose wire? Bad switch? Belt too loose? Thanks again to all who help!

This isn't new for us.... this question gets asked about 10 times a mowing season.

Yes, it could be all the things you listed, except a loose belt. That is unless the PTO is not disengaging and the belt is slipping. In which case you will need to figure out which issue you have. You will have to check each electrical component that has to do with the PTO while it is acting up until you find the issue. With electrical problems, we can advise where to look, but you will have to find and repair the problem. Get out a DVOM and test light and start testing. If you need a wiring diagram, it can be found in the service manual. :beerchug:

Do you have any of the safety switches such as the reverse or the seat switch jumped out? How are the grounds such as on the reverse relay on the side of the instrument pedestal? On my 1772, i had an intermittent PTO as well. It turned out to be a broken wire. It was at the connector found for the PTO found on top of the cooling fan mounting. With my wife in the operators seat and engaging the clutch, I found if I moved the wires the clutch would disengage. The wires inside the insulation had broken from bouncing around while using the tractor WHILE leaving the insulation intact. One all the strands broke it out intermittently stop working. I ended up getting a new connector from Mouser.com, and recrimping both connectors. it's been rock solid since.

I had a similar issue when I first got my 2182. It drove me crazy until I started researching things. It is a low hour machine so I knew it wasn't electrical. There were two issues I found. The main issue was the battery. If you have a bad battery, your pto will constantly disengage. That solved my problem. However, since I was new to the 2182 I didn't realize there was a safety switch in the dash that EVERY time you would put it in reverse the pto would shut off. Very annoying. I fixed that problem quickly. Not sure if the older SGT's had this safety switch, but if not, either charge your battery or buy a new one. Invest in the stronger one with higher CCAs. If you had no prior issues and you haven't replaced your battery in a while I would try this route first. After fixing these two issues I have not had any more issues with the pto shutting off unless I hit a bump and my A** lifts off the seat and the pto shuts off.

As a note to all this: The CCA's of the battery DO NOT affect it when the engine is running. The reason your battery was the issue is because it likely had a bad cell and was drawing too many amps from the charging system. Yes, it was the batteries fault, but not because it was too small. Could also have been that your charging circuit was weak and the battery was bad. A PTO clutch coil only pulls like 3-5 amps when in use.

All machines built after 1981 (I think, may have been '83) had the reverse cut out relay (dash switch on the hydro lever).

Yes. Was not saying that the CCA was the issue but was recommending getting a higher CCA (premium) battery instead of a standard battery when replacing it. Makes a difference when starting. Anyway, try a new battery. May fix your problem. When buying a battery, go for the higher CCA battery instead of standard if you have the option. Dont start freaking out over electrical issues before trying a fresh battery. You can always return the battery.

I had similar problem, years ago, with a 1572. Finally found the problem in the plug for the rear PTO. I do not have rear PTO so there was a jumper. It is right behind the battery on the 1572 so there was some corrosion in the plug and it would drop enough voltage across the jumper connection to drop out the PTO.

Learn something new everyday. My 2182 does not kick the PTO off if in reserve, or if your butt is not on the seat. I thought that was just the way they were made? Figured it was made before all the safety stuff started.

Now I'm wondering if the previous owner just disabled them.....ummm I will have to look nice time I'm in the shed.

I had the same issue with my 782. The PTO would not re engauge when hot and sometimes would just drop out. What I found out was the air gap was too wide and when everything heated up the coil could not hold it. I adjusted the air gap and have not had a issue since. There are three slots in the clutch to slip a .017 feeler gauge in to check clearance. They are next to the adjusting bolts. to tighten the air gap tighten the bolts a little at a time and check then move to next bolt. To get them all correct you may need to do this more than once. ALSO BEFORE TRYING TO ADJUST SPRAY THE NUTS WITH SOME TYPE OF PENETRATING OIL. You do not want to twist off the studs. Your operators manual should show you the procedure. I know the one for my 782 and 1872 show the procerdue. The 782 manual says .010-.015 air gap but if the clutch drags to increase to .020, the 1872 says .017 air gap. I have always adjusted mine to .017. I am not saying this is your problem but if it is not electrical a good thing to check for and also it cannot hurt to check it. What happens is the outer ring of the clutch cover acts as a pto brake and over time it and the armature wear increasing the air gap. Let us know what you find. Good luck
Tom
Here is a video showing how to adjust.
https://youtu.be/1YvPZMbASCE

Thanks!
 

Thanks for all the things to look into. Forgot to mention that the safety switch under the seat has been disengaged (almost from day one). Also, the battery should be good, we replaced it 2 years ago, and yes with a higher CCA than the old one. I now think it's probably a wire, and will look into it with all of your suggestions.

I found it so frustrating when my PTO was cutting out, I ran 2 wires from the PTO connector by the fan to a DVM. When I would be mowing, I had the meter turned on to watch the voltage at that point to see what it was when the clutch dropped out. I believe that was probably the only way I could have found the broken wire inside of the insulation jacket.

Next step?
 

Ok I have a wiring diagram and a test meter...what would the next step be, this is new to me!

Let me see if I can take a picture to describe it better. Like they say a picture is worth a 1000 words.

I'm willing to do the work, but really need guidance regarding wiring. I have a wiring diagram, but since the wires aren't laid out neatly like the diagram, in reality how do I go about this? What should I remove to get to the wiring, if anything beyond the sides and lifting the hood? Don't mean to be slow about this, it's just a little new for me. Thanks.

Sorry for the delay, BLASTED internet keeps dropping out and has been out for the last 3 days - #@#%&#*#$

I connected a DVM as shown below. However not shown in the pictures, use duct tape to hold the leads in place and also hold the meter in the spot show so I could see what the voltage to the clutch was when it dropped out. I needed to determine whether it was the clutch winding that was bad or the circuits in the tractor that was causing a problem. when I saw the clutch dropped out AND voltage was still applied at the point the meter was connected, it greatly narrowed the search to what the problem was and where it was located. In my case, the voltage was there when the clutch dropped out. While having the wife in the drivers seat with the PTO on, simple movement of the wiring AFTER the connector exposed a broken wire that I was able to repair.

Attachment 79235
Attachment 79236
Attachment 79237

Explain wiring on 1772
 

Here are some pics of my Cub's wiring. The safety shut-off is disengaged and has been for quite some time. Is it possible a wire was pinched when everything was put back together after resolving the gas line issue? Note the white wire near the rear lights wire - what is that for? The colors don't correspond to the wiring diagram from the manual, so it's a bit confusing.

If I recall correctly, the white wire is used for the rear PRO clutch when and if it is installed. Without a rear PTO it is not used. Something else to check it the relay on the LH side of the console. A bad relay or bad ground at the relay can cause intermittents as we as could a bad PTO switch on the dash.
On a couple of my diesels, I also had an intermittent PTO. In each case it was something else that cause the problem. On the first time I had the problem, the field coil itself of the PTO would open up when hot after about and hour and a half of mowing. When it cut out, I grabbed my meter, disconnected the connector for the clutch and measured the resistance while hot and found it open. As it cooled, it would start to regain continuity again. This one only happened once or twice a year but after the 3rd year would happen about every other time while mowing. The next time I had this was on another diesel. This time it would happen after I would hit a bump. I thought I was coming off of the seat, but that was not the case. The clip on the fan bracket was holding the clutch power lead in place BUT the connector next to it would bounce all the time. It eventually broke the wires off of the connector inside the insulation. When I connected the meter as int he photos, one wire felt real flimsy and power was still applied. A little pull test on the flimsy wire revealed the broken conductor as the insulation slipped off the crimped connector. The last time I had a problem, the connector for the reverse safety switch by the hydro lever had a bad crimp and was actually melting the insulation. A new crimp fixed that one.