OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar 33 Clutch Removal

Hello all,

Long time stalker, first time poster. I was gifted a model 33 from my father and have decided to strip it down and give it some much needed attention, including an engine replacement. I've already learnt so much from this amazing community - many thanks!!

I've managed to loosen the nut from the drive shaft, but unsure if the clutch housing is just pressed on or screwed on. Assuming just pressed but wanted to check before using some force.

If pressed, would a gear puller be the best option to remove?

2021-02-13 13.41.01 by Stuart Bridge, on Flickr
2023-09-23 16.13.58 by Stuart Bridge, on Flickr
2023-09-23 16.14.09 by Stuart Bridge, on Flickr

Thanks,
Stu

I thought I'd read most of the 33 posts, but came across the answer here:

https://www.outdoorking-forum.com.au/forum/u...r-scott-bonnar-33-project.html#Post88924

That thread that the nut screws onto has a cut along it`s length, as the nut tightens up, the threaded "collar" clamps down on the output shaft. By all means use a puller, I have used a piece of hard wood to tap the threaded collar and that usually separates the collar from the shaft - remember that the parts of the clutch are cast steel (machined down), so tread carfully.

NB the spring inside the SB33 clutch is longer than the SB45. The bearings on the roller, ect are the same as SB45`s bearings
(I purchase a kit of bearings for SB45 to rebuild my SB33. I like the SB33 because it is a part of the history of Scott Bonner and I enjoy restoring old machinery.

I have just purchased a Bon Mow 19 (cira 1950`s) as the next project.

Thanks Malcolm - appreciate the feedback. I'd seen in another thread that someone had damaged the cast steel clutch with a bit too much effort so was mindful not to repeat that with mine. I'll try tapping the threaded collar with some hardwood first - if no luck then I'll source a gear puller.

Good to know that the I can use the SB45 clutch bearing - I'll replace the old one as it's a bit rattly now.

I found out that the mower was purchased from new by my grandfather, passed on to my dad and now me. Love having that piece of history in the family.

So my quick engine replacement has turned into a full-on reno. I've now removed the drive belt, chains and sprockets, and about to embark on removing the cutting reel. Unlike the model 45 that has a split bearing housing, the model 33 has single piece bearing housing. I'm assuming then that the only way to remove the reel and rollers is to unbolt either the left or right side frames?



Right bearing housing:


Left bearing housing:
2023-10-10 11.21.01 by Stuart Bridge, on Flickr

Hi stulandr,

If you can't move the reel on one side under the side plate so you can pull the reel out ,then you will need to remove the side plate .

I can't see in the images if the reel will drop down on one side it will depend also if the hole on one side plate is bigger than the
reel shaft to allow the reel to be angled when removing the reel.

Cheers
Max.

Thanks Max. Yes, it appears that the hole on the left side plate is bigger than the reel shaft. Should allow me to angle the reel to remove. I'll give that a go.



Cheers,
Stu