OutdoorKing Repair Forum Forums Welcome to Outdoorking Forum HELP Area Introductions Gday all from Brisbane

Hi everyone, I have posted a couple of times already but I figured an introduction of sorts was in order as well. Found this site looking around on the net for discussions on mowers and such like.
My name is Kelsey, I'm 24, used to work at Oxley Golf Club where I did an apprenticeship in turf management. Currently not working in the industry, but I've been wanting to get a self propelled cylinder mower for a while, only just got around to it in the last couple of months. But, finally got one, it's a Scott Bonnar model 33, 16" 12 blade cylinder, 3hp Kirby Tecumseh 4 stroke engine for $200, I'm guessing it used to be a greens mower in its younger days with that many blades on it. Just started to restore it a bit, it's in perfect working order just looks a bit tatty so it's mostly an appearance restoration than anything else, except the blades which needed a full sharpen. Cuts beautifully now. I'll post pics when I've finished doing it up, I don't really have any before photos yet.

Cheers,
Kelsey

Hi Kelsey, and a warm welcome to the forum. It's great to have another Scott Bonnar owner on board.
on scoring a Model 33, first introduced in 1960 and manufactured in Adelaide. A good strong chassis and, for it's time, a strong little Tecumseh engine. Here is an illustration of a Model 33 with the Tecumseh for those members that have never seen one....as you can see, this was the mower that inspired the famous Model 45. Please disregard the title at the top of pic.I came a cropper!!

The caption at the bottom is correct!!
Once again Kelsey,

Thanks Darryl,
It was advertised as a 45, but when I got it home and looked at the tag it says Model 33. Either way, now that I've restored the blades' sharp edges it produces a super cut. I wish there was some way of finding out how old it is, the serial number doesn't really give much away, so far all I can gather is between 1960 and somewhere in the 1970s, when did they stop production of the 33?

Cheers,
Kelsey

Here's a couple of progress photos from redoing the paint job/decals:
So far just started on the chain case cover and the catcher. I've done the black Scott Bonnar writing, and the red bits in the SB logo thing on both. (Needs a bit of fixing up on the catcher which I'll do when I do the white, had to pretty much guess where everything used to be on that). Also applied a first coat of green paint. Probably could use some panelbeating too but I'm not too concerned about that at this stage.

Good work there Kelsey, It will look great when you finish, It will also give you many hours of mowing pleasure.

Thanks mate,
I'm looking forward to getting it all finished, but it's fun to do it as well and see how it turns out as I go along. I think what I like most about it is the 12 blades, it's perfect for the type of really short lawn I like to keep, although I'm thinking about looking for another one with less blades for winter when I prefer to leave it a little longer.. or maybe having a spare cylinder made up so I can interchange them with the seasons. Haven't worked that one out yet.. lol

Cheers,
Kelsey

I just put a new belt on it on the weekend.. the one that goes around the pulley on the cylinder and after about 3 mows it's already got a massive tear in it Just wondering if it's because it's a cheap belt or is there a correct tension they have to be at? I also noticed it was just slightly out of line on the pulleys.
Cheers,
Kelsey.

Kelsey, something is obviously wrong with your belt drive. Can you post a picture of it please, in case the belt is incorrectly routed or adjusted? The pulleys should not be out of line, it sounds as if there is an assembly error somewhere, but that should not destroy the belt in 3 mows.

Hi Grumpy,
Yeah, that's what I thought, 3 mows is ridiculous. I had a look at it earlier and the belt was loose, I turned that conical thing on top of the mower that's attached to the top pulley (not sure of the term for it), and it'd spin the pulley but the belt stayed put. But yes I'll try and get some pics after work tomorrow.

I've got a couple of pictures.. hope they help.




As you can see on the second one, the belt/pulleys and chain are out of whack a bit. Also, the shiny part on that cylinder blade stops before the end of it, I noticed that the cylinder doesn't line up flush with the edges of the bedknife, so I'm just gonna take it all apart and get it all lined up properly.

It does look as if the belt pulleys have been incorrectly assembled. The illustrated parts list shows two different configurations for the model 33: 330026, which was chain drive; and 330413, which was belt drive. Yours is obviously 330413 since it is belt drive. I am doubtful that the large hex nut on the inboard side of the top (engine shaft) pulley belongs there. Also, there are parts on the inboard side of the cutter pulley that don't seem to belong either. It looks as if someone may have deliberately spaced the two pulleys outward for some reason, but the two idlers may not be cooperating with this. I suggest you look carefully at the illustrated parts list and assemble your mower exactly in conformity with it.

Cool, where can I get a hold of this illustrated parts list?

It is in the parts and manuals section of this site:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=6371#Post6371

You have to subscribe to get there, however. The item you want is titled Model 33.pdf

I can't find anything on that link to subscribe to it?

Kelsey, the link to the subscription process instructions is one of the first posts you see in any of the forums, but here it is anyway:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=14037&an=96#Post14037

Thanks Grumpy,
I have had a look at the drawing, and it appears that hex nut on the engine shaft pulley is there, but on the cutter pulley there's nothing on the inside, so perhaps that could be the problem. Time for some investigation on the actual machine I think.

Kelsey, my reading of the chassis illustration for model 330413 is that there is no component inboard of the engine shaft pulley until you get to the other side of the mower's sideplate - the next component is No. 37, the Engine Shaft Washer. The point is that on the illustration it is on the inboard side of the side-plate, not the outboard side. On your mower it is on the outboard side, with a large nut that I haven't found on the illustration so far.

Hi Kelsey and grumpy, Have a look at the cutter clutch (engine shaft) pulley illustration (increasing magnification).. Component number 147 and I think you'll find that the large "hex nut" is, in fact, an integral fact part of the pulley. It is there to assist in pulley removal...you can get a spanner on the 2 long flats to hold it whilst undoing the nut. It well may be the same for the cylinder reel pulley...
Kelsey, are there 2 long flats on the lower pulley?

IMO, I think the probs may well lie in the cylinder reel bearings being shot....possibly the engine shaft bearing may need replacing as well. This would account for the uneven wear on the reel and not lining up on the bed-knife. This would make adjustment of the reel to bed-knife clearances impossible.

So the pulley is keyed to the shaft, and has two flats on its inboard side so you can hold it with a spanner while you undo the retaining nut on its outboard side. That means the pulley is drawn onto the shaft as far as possible, until it hits a shoulder on its inboard side. Since the inboard end of the pulley is just about up against the shaft bearing (attached to the side plate) the lateral position of the top pulley has to be right. And the two idler pulleys seem to line up with the top pulley, they just don't line up with the bottom pulley. And the problem with the bottom pulley's location may be that the reel's axle shaft is out of position: too far toward the pulley side of the mower. I don't know what is causing that, but it probably needs to be lifted out and its components and their sequence compared with the illustration. I can't tell if Component 148, Cutter Pulley, has something inappropriate on its inboard side or not - from the illustration I don't think there should be anything between it and the inner ring of the reel bearing.

Well, me and dad took it apart, turns out Darryl was pretty on the money, the bearings weren't shot, however they were out of alignment in the housings, so we cleaned the housings out and some crap off the outer of the bearings and put them back in where they are meant to be, new belt on and it has stayed intact, so it seems that was the issue. Also the cutting cylinder is where it should be now. There aren't the 2 long flats on the lower pulley like the top one, but those "inappropriate" things on the inboard side of it are actually part of the pulley itself. It was the bearings and housings being dirty that were causing them, and hence the pulley, to be out of alignment. Now I can get on with redoing the paint job
Cheers,
Kelsey