Speaking of safety...

[om21braz]

I had a close call of sorts today. Mowing w/ self-propelled push mower (Deere JX75) w/ bagger attached. I was mowing new grass for the first time, super-wet, and had already emptied the bagger several times. The mower has a blade-brake clutch on it, so I simply release the safety bar, blade cuts off, pull the bagger off & empty. Then pull the safety bar back against handle, engage the pto lever and go again. Full again, stop mower, release bar - blade stops cold. Now empty bagger, grass chute full too, put my hand in the chute to push a clod of wet grass thru - not into the blade area, but close. I replaced the bag and much to my surprise the blade engaged itself ! Safety handle is in off postion and pto handle in off position. Thank the Lord my hand was not in there then. Now the blade will not disengage regardless of what I do, turn mower off & restart blade is engaged during start-up, etc. Any ideas before I tear into it ? What I really don't get is it engaging itself - electric pto contacts welded maybe ? Any ideas appreciated while I attempt to find a manual displaced a few years back.

 

[LBrown59]

Lesson learned:
Don't stick hand in there with engine running.

I had a close call of sorts today. Mowing w/ self-propelled push mower (Deere JX75) w/ bagger attached. I was mowing new grass for the first time, super-wet, and had already emptied the bagger several times. The mower has a blade-brake clutch on it, so I simply release the safety bar, blade cuts off, pull the bagger off & empty. Then pull the safety bar back against handle, engage the pto lever and go again. Full again, stop mower, release bar - blade stops cold. Now empty bagger, grass chute full too, put my hand in the chute to push a clod of wet grass thru - not into the blade area, but close. I replaced the bag and much to my surprise the blade engaged itself ! Safety handle is in off postion and pto handle in off position. Thank the Lord my hand was not in there then. Now the blade will not disengage regardless of what I do, turn mower off & restart blade is engaged during start-up, etc. Any ideas before I tear into it ? What I really don't get is it engaging itself - electric pto contacts welded maybe ? Any ideas appreciated while I attempt to find a manual displaced a few years back.

 

[Bird]

I'm not familiar with that John Deere mower, and you don't say how old it it, but I have a Toro with their "blade override system" that sounds similar. The manual says to clean the "blade brake clutch shield" yearly, which simply entails removing the blade and all the other parts will fall out to be cleaned and put back. It sounds as if your clutch is stuck and won't release, but that's just a wild guess on my part.

 

[om21braz]

Point taken & well understood LBrown. Bird, mower is approx. 4 yrs. old and cleaned regularly - last cleaned 2 wks. ago when blade was resharpened. The clutch is sure fixed itself in the engaged position, just tough figuring it engaging itself bypassing all safety devices on it's own. Well, it's now cleaned off and ready for disassembly which I'll begin tomorrow after borrowing a puller that probably will be needed.

 

[Bird]

Be sure and let us know what you find out. I've not had that happen on mine . . . yet, but who knows, it might happen. You can tell from the sound when the blade is disengaged, so yes, I've shoved some grass through just as you said you did, and to tell the truth I never thought about the blade engaging like that. If it failed to disengage, I could understand that, but to disengage and then engage again is really surprising.

 

[shot_gun]

I have one of these mowers and I'm a little scared because I've done the same not thinking and being in a hurry. I have replaced the lower bearing in the clutch because it seized and would not let the blade stop turning. The bearing made a whole lot of noise before it finaly seized. This may be your problem. Either way it sounds like something in the clutch has gone ary.

 

[Fordlords]

The air gap in an electric PTO clutch is ony a few thousandths of an inch. This is the gap that is present between the drive pulley and the friction material (drive end) when the clutch is disengaged. The clutch can get mechanically stuck on if friction material breaks off and lodges itself in the air gap, if a lot of foreign debris gets in the air gap, or of the collar the drive pulley moves on gets dirty and the springs can no longer move it away from the friction material when the clutch is disengaged.

Proper procedure for putting hand anywhere near a mower blade is of course engine off, and spark plug wire removed also. No reason to be in a hurry, because you'll be in even more of a hurry if you cut your hand off- hurrying to the emergency room.

-Fordlords-

 

[om21braz]

Well, finally got a look at things and clutch (mechanical), at a glance, is disengaged as the bottom is settled on the brake disc. Upon closer inspection it actually is very loose and not setting concentric w/ the crank end. Did'nt seem terribly out of balance when running as you would think. No good place to put a puller. Something internal, arrgh... Whatever went wrong, it did so without any warning. After some head scratching, I called a fellow who is a displaced Deere parts man - fortunately now at the local Kubota dealer. After some discussion he noted the clutch assy. is one part (approx. $140.00) and previous removal methods have led to destruction of one motor at the Deere dealership. Others with much age at all being removed the old acetylene/oxygen wrench way. If I get a chance tomorrow I'll get the motor off the deck and go from there. A PB Wrench bath is first on the list for it, and go from there - I'll report back when I've mashed a finger, got a shoe full of slag, got the clutch off or a combination of all the above.

 

[Bird]

That does not sound good; sounds as if it might be expensive and/or painful.

 

[om21braz]

Well it turns out a retaining ring broke allowing the internal hub to engage the assembly on it's own. No torch required for disassembly, although I did damage the crank-end bolt trying to break it loose. Evidently it is a common problem as a new bolt is included with the clutch mechanism. New unit is installed and will be ready to go tomorrow - good thing as the new grass needs cutting again.