Tractor /mower PTO clutch fixable?

[Harry Bloomfield]

The tractor broke one of its drive /motion belts, in the process of investigating that, I found another issue..

The PTO clutch driving the cutting deck is not fully engaging, I assume the clutch slipping. I had an idea something wasn't quite right sometimes, when asked to do a lot of work, but now I know its slipping when its supposed to be fully engaged.

The PTO pulley/clutch is an MTD 717-1787A - this one..

Which is shown in the photo inverted. The small pulley goes uppermost, driven all the time the engine is running. The lever coming out of the side engages and disengages the drive to the larger deck drive pulley.

I have not got the unit off yet, to take a proper look at it, but wonder(as these are quite expensive) if anyone might have refurbished one of these clutch mechanisms?

The pan shaped part with the lever coming out, obviously remains stationary, but I haven't yet worked out what prevents that pan rotating.

[Harry Bloomfield]

Harry Bloomfield has brought this to us :

Er, forget that I think I have solved it...

I managed to push it under cover to work on it, turned it over a little way onto it's side, to get a better look at the issue(s).

Even with the PTO clutch engaged, I could with a bit of effort turn the PTO pulley in relation to the engine output shaft.

A very long bolt up from the centre, through the PTO into the end of the crankshaft, then a very large but thin outer nut above that, which was quite loose. I tightened the thin nut and the clutch appeared to lock up fully.

The thin nut is clearly visible in the ebay photo.

The only thing remaining, is to work out how that thin nut is supposed to be set, or how tight it is supposed to be. Plus of course waiting for my replacement motion drivebelts to turn up.

[Tim Lamb]

In message , Harry Bloomfield writes

That item is priced in dollars. Have a look at American sites discussing yard tractors.

Mind, it looks the same as that fitted to my mower (now marketed by Huskvarna) so pretty universal.

I suppose you could also ask the service dept at your local lawn mower supplier.

[Harry Bloomfield]

Tim Lamb presented the following explanation :

I did that earlier, trying to find out the part number, its cost and was it possible to service repair the clutch. They said that if the PTO drive was slipping the only fix was to replace the unit with new.

Guess they have maybe never come across that thin clamping nut coming loose before. I'm now guessing that the nut needs to be just as tight as it can be got - it seems to pull the whole assembly together. I'll add some Locktite, to make sure it stays put.