PTO Troubles

[Lakewalker]

I have a 2004 Cub Cadet Model 3204. Over the past year, I started having problems keeping the PTO engaged. After mowing for 20-25 minutes the PTO disengages on it own. At first, you could turn of the mower and let it sit for 30 minutes or so and the PTO would begin engaging again, Last time I tried engaging the PTO, it won't respond at all. The mower is kept on a weekend getaway location that is very remote so it is much, much easier to repair it on site rather than trying to trailer it to the local Cub Cadet dealer that is 35 miles away. Other than it being a bad clutch, is it possible to fix it adjusting the air gap? I have already replaced the PTO switch/wiring harness so I know that it isn't an issue. If it is the clutch that needs replacing, is it a hard job for a mechanically inclined person to tackle?

 

[Jack Vines]

I have already replaced the PTO switch/wiring harness so I know that it isn't an issue.

On my tractor, that wasn't true. Since your PTO will engage and run for quite a while, the most likely culprit is the wiring. Looking at the back of the PTO switch, you can see there are wires connected all over the tractor. On mine, using reverse disengaged the PTO and there were several other safety/lawyer interlocks. One or the other of them were always failing or randomly shorting out. You can test the hypothesis by just temporarily bypassing the OEM PTO switch with a simple toggle switch.

On my tractor, the final solution was to bypass all the interlocks and use a simple on-off pull switch for the PTO. This ensures the PTO will always engage, but it won't disengage until you turn it off.
CAUTION - this is my solution only and not intended to encourage anyone to endanger himself. You make your own decisions.

jack vines

 

[Lakewalker]

On my tractor, that wasn't true. Since your PTO will engage and run for quite a while, the most likely culprit is the wiring. Looking at the back of the PTO switch, you can see there are wires connected all over the tractor. On mine, using reverse disengaged the PTO and there were several other safety/lawyer interlocks. One or the other of them were always failing or randomly shorting out. You can test the hypothesis by just temporarily bypassing the OEM PTO switch with a simple toggle switch.

On my tractor, the final solution was to bypass all the interlocks and use a simple on-off pull switch for the PTO. This ensures the PTO will always engage, but it won't disengage until you turn it off.
CAUTION - this is my solution only and not intended to encourage anyone to endanger himself. You make your own decisions.

jack vines

Thanks Jack, I will try bypassing the PTO switch with the toggle to see if that will work. I have also been told that you can adjust the air gap on the clutch. I will try each method and hopefully will eliminate the problem.

 

[rcbe]

Lakewalker - before you start responding to half-baked troubleshooting suggestions, wise to know exactly which type of PTO system was built into that machine. I'm thinking you have a "E-vac" system which is considerably different from the typical Warner/Oguru electrical clutches used in other makes/models of machines.
May also want to thoroughly check the 'health' of your charging system and battery - if your PTO does require electrical power for initial/continued engagement... a failing battery CAN produce symptoms similar to those you described. Perhaps a battery LOAD test is in order or - if you've been hosing or powerwashing the machine - time to separate and clean all electrical connection points to bright metal with sandpaper or such. Good luck.

 

[Lakewalker]

RCBE,

Thanks for your reply. You are correct that it is an E-Vac system. I replaced the battery a couple of months ago so that shouldn't be it but you may have something in regards to sandpapering the electrical points. We do hose it down each after each use. My father, who owns 3 other Cub Cadets seems to think that it is the air gap adjustment. He stated that he had some similar issues with one of his and that by using a feeler gauge he was able to adjust the three bolts on the clutch to correct the problem. Hopefully it will be something simple and I won't have to replace the entire clutch.

 

[Bob_Bainbridge]

RCBE,

Thanks for your reply. You are correct that it is an E-Vac system. I replaced the battery a couple of months ago so that shouldn't be it but you may have something in regards to sandpapering the electrical points. We do hose it down each after each use. My father, who owns 3 other Cub Cadets seems to think that it is the air gap adjustment. He stated that he had some similar issues with one of his and that by using a feeler gauge he was able to adjust the three bolts on the clutch to correct the problem. Hopefully it will be something simple and I won't have to replace the entire clutch.

The gap adjustment applies only to the older electric clutch type PTO. Yours is engaged by vacuum being applied to a diaphragm which moves an arm with idler pulleys against the PTO belts. Any vacuum leaks caused by cracked, worn tubing or hoses coming off will cause the PTO to disengage. The problem could also be electrical such as interlock switches, relay etc.

Bob B.

 

[Gator6x4]

Sorry I cannot help with your e-vac PTO problem. Here is a service manual for the 3000 series cub.

http://manuals.mtdproducts.com/mtd/GetFile.do?filename=770-10227.pdf

Here is a parts breakdown on the e-vac PTO on the 3204.

ARIPartFinder

 

[Lakewalker]

Bob,

Thanks for the clarification in regards to the air gap adjustment. I can now rule that out. As you point out, it sounds like I need to check for vacuum leaks and loose hoses. Since I have replaced the PTO switch, would that eliminate the possibility of it being the interlock switches, relay, etc...?

 

[Lakewalker]

Bob,

Thanks for the clarification in regards to the air gap adjustment. I can now rule that out. As you point out, it sounds like I need to check for vacuum leaks and loose hoses. Since I have replaced the PTO switch, would that eliminate the possibility of it being the interlock switches, relay, etc...?

 

[rcbe]

At the risk of muddying the waters (no pun intended), your practice of hosing down the machaine after each use does give rise to much concern for ANYTHING electrical on your unit. L&G powered eqpt are not designed/built to withstand liquid moisture - garden hoses and power washers are a sure way to cause electrical and lubrication related failures at any number of places in the units. Much better to use compressed air or leaf blower to get trash/dust off machine... and a sponge bath on outer sheet metal/plastic for waxing prep. You can't wash 'em like a car.
So, you may now be seeing some of those electrical corrosion problems coming to bear - mebbe. The other thing is a thorough vacuum system leeak check as the machine is now close to 10 yrs old..? But, do lose that hose.

 

[The kid]

I had the exact same problem and wrote it off for a year or two. After a bit of research I started doing some troubleshooting. I would put a trickle charger on the battery and at first the clutch would kick in every time. Then about half way thru six acres and shut off the clutch to pick up sticks. The clutch would not re- engage. I'd wait about an hour and start the mower up and it would work. After awhile, same thing. After logically looking at the clutch with needed voltage and amperage to work. My battery was barely strong enough to start the engine but wouldn't engage the clutch.

Next out came the multimeter. I started at the source. Battery was 11v. Next, I went to the regulator or bridge rectifier on the side of my Kohler 25. It showed shorted. I got on the net looking for like problems. The most common was a loose magnet under the magneto. Loose magnet? Inside the magneto / flywheel there is an array of magnets that rotate around a "stator" or alternator which develops 18v input to the rectifier. If a magnet comes loose while the engine is running it destroys the stationary stator. Think of your engine as a small 15 amp generator. With the stator destroyed. No voltage going to the rectifier/regulator and probably shorting and destroying it as well.

The stator, magneto / flywheel and rectifier had to be replaced on mine. Yours may only require a rectifier. The rectifier has three wires. The two outside should be marked 18v. The middle is your charging voltage. Remove the three wires, marking them first. If the battery is charged start the engine and measure the AC voltage on the two outside wires you removed from the rectifier.. There should be 18v AC present. If not your stator is bad. If 18V AC is present the the rectifier is bad. Reconnect the stator wires to the rectifier and with engine running measure the DC volts on the center rectifier terminal which should read around 14VDC. Hopefully you won't have to replace the flywheel magneto, stator and rectifier as I did.

 

[Bob_Bainbridge]

Bob,

Thanks for the clarification in regards to the air gap adjustment. I can now rule that out. As you point out, it sounds like I need to check for vacuum leaks and loose hoses. Since I have replaced the PTO switch, would that eliminate the possibility of it being the interlock switches, relay, etc...?

No, an interlock switch like the seat could still be a problem. I'm not sure if the brake interlock is in the circuit also.

Bob B.

 

[RONABNER]

Recently the PTO on my 2009 Cub RZT 50 VT stoped working while in use. I had replaced the battery a week earlier, and the Delta PTO switch this past week. I am a real novice when it comes to a ZTR mower. Any suggestins?

 

[rcbe]

ronabner - first things first. start with a known baseline. Pull the "new" battery and take it to a qualified shop that will LOAD test it right in front of you. A marginal battery can cause a PTO to kick out as you describe and new lawn tractor batteries are somewhat notorious for being marginal as new. Also clean all cable contacts to bright metal with sandpaper while battery is out, including chassis ground connections.
Re-run and re-test entire sytem - post back with detail if still trouble.

 

[boilers413]

I have Cub Cadet 3184 and get my PTO to come on. Where do i go from the switch and what am i looking for