cub pto

jammin · May 1, 2005

the pto on my cub 2150 will not disengage. as soon as the engine is started, the blades start turning, even when the toggle is off. when i turn the pto toggle to the on position the blades continue and the seat interlock works as designed. the seat interlock does not work, as is the design, when the pto toggle is in the off position. i have replaced the pto toggle switch already. no change. electrical grounds seem to be all good. can the pto fail in the running position? any insight would be appreciated. thanks in advance.

Outlander1 · May 1, 2005

I think a salesman told me that was some kind of an electromagnetic clutch? If so there must be some metal elements in there that become activated through some electrical process? I would guess that some water got in there and rusted those metal elements in the on position? Probably totally wrong.....

dbear · May 1, 2005

Don't know about the CC 2150, some electric clutches have adjustable air gap. If yours has three bolts w/springs covering them around the outside edge of the clutch, topped off by lock nuts, it's an adjustable one. In your case, the gap is probably too close. Should be somewhere in the neighborhood of .017".

JTKub · May 1, 2005

This sounds like a bad ignition switch. The ignition switch is tied into the PTO circuit & must be shorting due to worn contacts. These electric PTO's fail in the 'open' condition so it's gotta be getting 12VDC when it shouldn't be (bad ign. switch)
G/luck
Joel

Bob_Bainbridge · May 2, 2005

( This sounds like a bad ignition switch. The ignition switch is tied into the PTO circuit & must be shorting due to worn contacts. These electric PTO's fail in the 'open' condition so it's gotta be getting 12VDC when it shouldn't be (bad ign. switch)
G/luck
Joel )

Analyzing the symptoms given I believe that the problem has to mechanical - the PTO clearance is too close or is binding. The ignition switch works as designed - turns the ignition on and starts the tractor - shuts the tractor off when turned off. The PTO switch, which was replaced once, also must be working since the seat interlock shuts the tractor off when the PTO switch is ON and doesn't shut the tractor off when the PTO switch is OFF. This narrows the problem down to the fact that the PTO is engaged no matter what happens electrically.
My 1450 used to fail the opposite way - it wouldn't engage. I was always able to fix it by adjusting the gap.

Bob B.

JTKub · May 3, 2005

Yep, something is either jammed in their causing the clutch to stay live ALL the time, or the clutch is being energized as soon as you toggle the key to on. I don't see how the air gap will get smaller with wear, causing the clutch to engage, but I guess a SERIOUS layer of rust could do it. Typically the gap gets bigger as clutch ages. Jammin- can you verify if the clutch is live with the key out of the ignition?
G/luck
Joel

JackinVirginia · May 3, 2005

If it is like mine, the outer shaft to which the pulley is molded can actually get so rusty inside that it binds to the crankshaft. Remove the bolt with an impact wrench and see if the pully slides off easily--if not that may be your problem.

jammin · May 15, 2005

just to follow up regarding the pto on my cub. after double checking the electrical and then e-mailing cub tech support i decided to bring it to a local dealer. it turns out that the PTO field coil failed and was grounding through the PTO housing, completing the circuit causing it to run constantly. the PTO had to be replaced. i must say that cub tech support was very responsive and even e-mailed me the electrical schematics. the dealer said that the 500 hours i got out of the PTO was pretty normal for failure to begin/occur. thanks for all your ideas. all were appreciated.

Bob_Bainbridge · May 15, 2005

( just to follow up regarding the pto on my cub. after double checking the electrical and then e-mailing cub tech support i decided to bring it to a local dealer. it turns out that the PTO field coil failed and was grounding through the PTO housing, completing the circuit causing it to run constantly. the PTO had to be replaced. i must say that cub tech support was very responsive and even e-mailed me the electrical schematics. the dealer said that the 500 hours i got out of the PTO was pretty normal for failure to begin/occur. thanks for all your ideas. all were appreciated. )

I don't know about the 500 hours statement. I had 1100 hours on my 1450 when I traded it in and the only problem with the PTO was adjusting the clearance a couple times when it failed to engage. I would gladly trade the vacuum/double belt PTO on my 3235 for the old electric one. I've never looked into the safety issues with the vacuum PTO. I have the bagger and when the grass is wet, the chute clogs and I have to remove the chute and clean out a half-bag of grass. I disengage the PTO, of course before sticking my hand in there but I don't usually shut off the engine. I don't know if there is any vacuum failure that could cause the PTO to engage or not. I guess it could definitely happen with the electric PTO considering the problem you had.

Bob B.