F935 PTO not engaging

[psween]

Have an F935 that the PTO won't engage with the switch. The solenoid that retracts the PTO brake band and engages the shaft is free to move, has power going to it when switched, but doesn't engage. If you manually move the solenoid it will engage and keep the PTO running until you shut the switch off, then it disengages as it should, but won't re-engage unless you manually push the solenoid shaft again. Any ideas? It almost acts like one of the safety interlocks is preventing engagement, but power is getting to it, so that shouldn't be the issue. Maybe just a bad solenoid? I'll pull the switch next and see if it's got an intermittent problem, but again, power seems to be getting through. I'm open to any suggestions.

Patrick

P.S. This year obviously has the PTO switch, not the manual lever/magnet combo on some F935s.

 

[billymagg]

Have an F935 that the PTO won't engage with the switch. The solenoid that retracts the PTO brake band and engages the shaft is free to move, has power going to it when switched, but doesn't engage. If you manually move the solenoid it will engage and keep the PTO running until you shut the switch off, then it disengages as it should, but won't re-engage unless you manually push the solenoid shaft again. Any ideas? It almost acts like one of the safety interlocks is preventing engagement, but power is getting to it, so that shouldn't be the issue. Maybe just a bad solenoid? I'll pull the switch next and see if it's got an intermittent problem, but again, power seems to be getting through. I'm open to any suggestions.

Patrick

P.S. This year obviously has the PTO switch, not the manual lever/magnet combo on some F935s.

Sounds like you are on the right track, my new to me, old F935 has the manual lever/magnet combo, but someone has wired a switch into the system and bypassed the old one. Still I enjoy running the 935, I just wish I could find a 60" deck to replace my 72". We recently purchased a 2 year old Scag, with a 61 inch deck and 30 horse Kawasaki at the campground where I volunteer, so I purchased the 935 to use in the country....

 

[Jus10]

Sounds like you are on the right track, my new to me, old F935 has the manual lever/magnet combo, but someone has wired a switch into the system and bypassed the old one. Still I enjoy running the 935, I just wish I could find a 60" deck to replace my 72". We recently purchased a 2 year old Scag, with a 61 inch deck and 30 horse Kawasaki at the campground where I volunteer, so I purchased the 935 to use in the country....

I have a 2006 F911 (900+ hours) and just recently experienced a similar thing. The PTO switch will move the solenoid and "open" the clutch brake, but the PTO shaft will not spin. I mowed for about 10-15 minutes and all of a sudden the PTO shaft stopped spinning even though the PTO was still "engaged" and the clutch brake was "open". I can spin the PTO shaft with my hands while the clutch brake is open and closed. Is that normal? I did just add some hydraulic fluid to the reservoir, but I wouldn't think that would have anything to do with it. The seat safety has been bypassed. Thought about the brake doing something funny, but that would disengage the PTO and "close" the clutch brake, right? Does anyone have any thoughts on this? Thanks in advance.

 

[Jus10]

I don't always get 12v at the pto clutch, very rarely. I do get 12v at the plug that goes to the pto switch. So I put a new switch in and I still have the same problem. Made sure it's not an issue from the brakes. Anyone have any ideas? Typo in my previous post, it's a 1996 F911.

 

[billymagg]

I don't always get 12v at the pto clutch, very rarely. I do get 12v at the plug that goes to the pto switch. So I put a new switch in and I still have the same problem. Made sure it's not an issue from the brakes. Anyone have any ideas? Typo in my previous post, it's a 1996 F911.

Jus10 how are the belts off the electric clutch, sure that's obvious, but mine did quit in heavy stuff, until I readjusted the belt tension, what would happen if you bypassed the normal circuit and wired the clutch hot??? just as a test, but that could be the problem???

 

[Nwatson99]

Okay let me see if I understand this, your switch is sending the proper current to the solenoid and the brake opens, however the pulley will not engage on the shaft?

 

[Carscw]

Is the clutch a adjustable one?

( no I did not look up the mower)

Sounds to me like it needs to be adjusted.

 

[Nwatson99]

Is the clutch a adjustable one?

( no I did not look up the mower)

Sounds to me like it needs to be adjusted.

I agree sounds like something is loose or frozen in there not allowing a full connection, one quick test you can do it take it off and hook 12 volt to it, if you see it move and hear a ding then it is releasing and should have engaged.
Might want to just order a pto assembly, replace it, and then tear into the other one and see exactly what is going on while checking everything to the specs called out into the manual. The benefit to this is, if you fix the old one you will always have a spare.

 

[Jus10]

Thanks everyone for your responses. I was able to "fix" the problem late Friday night, just haven't been able to get back on here.

Although the solenoid was extending fully (so I thought this wasn't the issue) I pushed on it by hand just to see what would happen. Wouldn't you know it, by moving it about 1/16" of an inch it engaged the PTO. Now, the solenoid didn't move any further, it was the bracket that holds that solenoid. I don't understand the circuit enough (or at all) to know why moving the solenoid bracket just a little bit allowed for voltage to get to the PTO clutch. So, I was going to remove the battery (one of the cables didn't want to come off) and adjust some of the bracket bolts, but instead I have a bungee cord pulling on the bracket. Mowed great on Saturday. Just kicking myself for not trying the OP's solution even though I thought the solenoid was fully extended. Out $75 on a switch I don't need, but I'm cutting grass again. Hopefully this helps someone down the road.

 

[CAEMI]

Sounds like you are on the right track, my new to me, old F935 has the manual lever/magnet combo, but someone has wired a switch into the system and bypassed the old one. Still I enjoy running the 935, I just wish I could find a 60" deck to replace my 72". We recently purchased a 2 year old Scag, with a 61 inch deck and 30 horse Kawasaki at the campground where I volunteer, so I purchased the 935 to use in the country....

If you're still looking for a 60" deck, I'll trade you mine for your 72" deck.