OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar cutting and clutch problems

Hi
I have owned a 17" Scott Bonnar 45 for a few years but it has sat in the shed in the last couple as we have a lot of grass to mow and so relied on a Honda rotary self propelled.
However I have recently built myself a 100 square metre golf green with the intention of relying on the SB 45 to do the job of mowing it close. I got it sharpened last year and haven't used it a lot since but when I got it going last weekend it is inclined to tear rather than cut the grass
It won't cut a piece of paper, it seems that there is more than a paper's width clearance between the bedknife and the reel - at least two papers width. Does it need resharpening or just adjusting?
I have also had some fun with the clutch - when I first dragged it out of the shed the cotter pin fell out but I have had the mower going expecting that to happen again but it hasn't - not sure that I trust it though. I have been reading a lot of the threads including excellent helpful videos from Deejay and it sounds like the cotter pin is a common problem
The grass deflector plates are forever becoming loose despite tightening them
Does anyone have any suggestions? I have photos but can't figure out how to load them

Hello Tim62A!

Welcome to the ODK forums. I'm sure we can help you here.
I have edited your first photo to embed it in your post.

For help in up-loading your pictures click HERE.

Administrator Deejay or experienced Technician Bonnar Bloke or other experienced members will assist you
once we have more photos, particularly of the reel/bottom block.

p.s. I see you have an Ogden Model B hand mower there as well. Nice machine!
-------------------------------
JACK.

Hi Tim62A, CyberJack, DeeJay and ODK members,

Firstly a warm welcome to this wonderful forum, I'm sure you'll have all your questions answered with the correct information.

Now firstly you say that the reel was sharpened around a year ago,

well I guess we need to know and this is not about laying blame, but more so to get an understanding of what has been done before we proceed with giving any advice.

1, was the whole job done by a lawn mower shop and was the bed knife replaced and sharpened at the same time, if so then I feel you just might have an adjustment issue which will be easily rectified as having two thicknesses of paper between the reel and bottom blade is not desirable.

The adjustment should be done in such a way that the reel is initially just touching the bottom blade and then backed off so that the reel just and I mean just clears the bed knife without touching it at all.

Now as far as the cotter pin is concerned and this really does concern me greatly as no captive cotter pin should be able to come out with the engine shaft still installed into the clutch half body.

Could you please be so kind as to post up some close up photos of the cotter pin area of the clutch so that we can assess it correctly and give you the right advice, but honestly I can at this point in time see that you are going to have to replace the clutch body with a new one that has the two set screws installed that pins the body to the shaft securely.

Anyway lets have a look at some photos first and we'll take it from there.

Cheers,
BB.

Thanks for your quick reply - well spotted on the Ogden, I have had that for at least twenty years, I think my dad bought it a clearing sale for $5. It still works but needs a sharpen. A subject for a different thread. Thanks for the tips on the photos, I will tackle that next

Thanks for your quick reply guys.
Here are some more photos. Without much difficulty I can remove the cotter pin with a bit of jiggling.
In terms of the history of the mower, I bought it second hand from Turf Machinery Services in about 2005. It cut like a dream but as you would expect it lost its edge over time and started to give a few problems, so it sat in the shed. Now I have the golf green I have a good reason to use it again and restore it to its former glory. It has a ten blade reel so hopefully will do the job.
I took it in to the local mower shop last year for a service and sharpen, they charged about $250, but I wasn't that happy with the job. It still seemed to tear the grass and the reel was running even when the clutch wasn't engaged. I have managed to fix that myself.
I think I might lash out and put a new motor on it - I am thinking about a Honda GX 160

Hi Tim,

Those photos are much better and it confirms what I originally thought. That clutch has been scrounged from an earlier machine and put onto yours. Your machine shouldn't even have a cotter as it is a Rover 45 and not a Scott Bonnar. The clutch has been taken from a mid to late 1970's SB.

Anyway I would not use it any more with a loose captive cotter pin and put a later style new clutch body on it that uses the two set screws. If you are going to replace the motor then I would do the job all in one go.

As far as the reel clearance is concerned I would first try to close up the gap between the reel and bed knife and see what result you get from that. It looks like the bed knife was changed not too long ago but whether it was machined prior to fitment I can't see at that angle of your photo. See if you can provide us with a photo looking at the top leading edge of the bed knife and we'll get a better idea.

Cheers,
BB.

Thanks BB
I have tried to take a photo of the top leading edge of the bedknife, but not easy to get at.
I guess I can work out what clutch parts are needed from the parts site, I assume I need to order all the parts. I also assume that I need to match the size of the clutch with the motor shaft, and if I get a new motor it needs to be either 5/8 or 3/4"?
It came with Scott Bonnar stickers, how can you tell it is a Rover?

cheers

Tim

Hi Tim,

From what I can see I think that the shop has merely just put a new bottom blade on without machining it, thus it doesn't mate up correctly with the blades on the reel. They have therefore adjusted the reel to not touch the bed knife and in places that clearance will be more than in other spots as the sole plate will more than likely have a slight bow in it. Common cop out by bad shops just taking money for nothing.

As far as the clutch issue is concerned you are correct that you will have to obtain the correct clutch body to match up with the engine shaft, so select you powerplant first and then purchase your clutch to suit.

Also be mindful regarding engine to handle bar clearance as some engines will fowl against the RHS handle bar up right.

I'm just wondering who's done the previous resto on this machine as Rovers came out in Rover Red and Kermit Green and Scott Bonnars were all Hammertone Green.

If you could show us the ID plate on the LHS of the chassis this will clear up what machine chassis this might be.

Cheers,
BB

PS I've just had another look at your first front on photo and I'd be pretty confident in saying that your machine is a Brisbane made Rover as it has the bolt through the chassis catcher rubbers fitted and it also has the circular Rover sticker on the handle bar shield plate. So technically it should have a Silver ID sticker on the LHS rear chassis rail near the clutch body.

Hi Tim62A, and a warm welcome to the forum.It's great to have another SB/Rover 45 owner on board, as we all like to learn new things and tinker here.

I must agree with BB here, this machine, without any evidence to the contrary, presents as a Rover 45, with its powder-coated Rover Red chassis. But, as we have seen here before, it could be a "wolf in sheep's clothing" and in fact maybe a genuine Scotty Model 45 tizzied up to resemble a Rover 45 by a previous tenant...

The ID tag (if fitted, or holes in the rear chassis rail) will give us a clear ID of what it is.
One can easily attach by nut and bolt the catcher rubbers, and repro decals are easily had, but we will get to the bottom of it for you.
If it is a Rover, the handle bar shield plate should be painted Rover red as well....you could, (if necessary), check underneath the decal, to see what colour is present.

Once again Tim, to OutdoorKing.

Hi DeeJay and Tim,

Just a point to ponder,

Regarding the rubbers its rather unlikely that the later rubbers have been fitted as why would one go to all the trouble to grind off the welds on the outside of the side plate and then punch out the original half inch square bar stubs so as to fit the later style rubbers, especially when the push on SB rubbers are readily available.

I'll have a bet here and say that it's infact a Rover 45, but as you've said DJ that the rear rail will tell us the full story.

Tim, can you please so kindly supply us with a close up photo of the rear rail around the clutch area ? and just in saying that I have had another really close look at the existing photos on this thread and it looks like the silver and black sticker is not there, so I wonder if there are two rivet holes remaining (which we can't see)or if someone has gone to all the trouble and welded them up, but I doubt it, but then again previous owners will do anything to try and add extra dollar value to make it look like a newer machine.

Cheers,
BB

Thanks BB and Deejay
I can't find an ID tag but there are holes in the rear chassis rail, see photo.
This mower came from Turf Machinery in Ballarat and I remember it was a resto of some sort - it might even be a collation of parts. The handle bar shield plate is plastic so I don't think it will be red under the decal, see photo
The clutch shaft is 3/4". If I go with a new clutch can I order a whole clutch assembly or do I need to order all the separate bits. I have looked at new Honda motors today and can get either 5/8" or 3/4" engine shafts

regards

Tim

Another photo from the side

Hi Tim,

Well I'd say that this photo is a tad inconclusive as there is what looks to be an ID plate painted over but it might be an illusion created by the grass that's all over it, well that's what the wife reckons anyway. Can you rub your hand over the top surface of the rail and confirm with us whether there is any or no sign of an ID plate or the remnants of an ID plate above the left hand hole that's visible in the photo.

I must admit that DeeJay has got me into a spin over the authenticity of this machine. There are just too many discrepancies that just don't add up.

Cheers,
BB

Edit : Now that you've just posted up that photo of the chain case while I was typing this shows us that this is not the correct sticker as that particular sticker is from the earlier Kermit Green Rover issued unit which was the model prior to the Red Rovers.

Hi Tim and DeeJay,

I'm starting to think your machine started out life looking something like this one but with a few parts cannibalised from other machines.



Cheers,
BB

That looks like quite a late model Briggs on that mower. So it should be a long way from worn out.
Model, Type and Code numbers off the cowl will allow us to date it, if you like.

Any particular reason you want to replace it? Not that a Honda isn't a far better engine; just that this may not be necessary.

Hi Tim and BB, I have known Keith Lewis from Turf Machinery Services in Ballarat, (now defunct), since 2005 and had many dealings with him over the period. He was an authority on all things Scott Bonnar and as an engineer could make up parts to suit, if necessary.

Now knowing that this machine was one of Keith's restorations, I can say categorically, it would be a 'bitzer', because he used to erect machines from all the used spare parts he had on hand...and he had heaps! ....They were an extremely good resto, and I have seen in person, one of his, here in Wagga....Just brilliant, complete with his pre-fabricated solid deck on a former twin railer!

Hi Gadge,
The motor runs alright but blows a fair bit of smoke. That is probably my fault for tipping the mower up too far trying to look underneath it. That might burn off after a while? It also seems to be weeping oil around the sump seal.
I am away from home for a few days but I can tell you that the plate on the mower says that it is Family YBSXS 1481HH. 274459

Cheers

Tim

Thanks Deejay and BB
Looks like it fits the picture pretty well. When I first got the machine in 2005 it cut like a dream.
Did you have any comments on the clutch question I raised last night?

Cheers

Tim

Yep, that's it. Tilting it will have made the sump oil flow into the valve spring chamber and its breather valve, which is vented through the carby throat. If you take off the air cleaner, I'd bet there's oil visible in the carby. It will make its way out eventually; just run the engine until the smoke clears!
Do you mean the crankshaft seal, or the crankcase cover gasket? If the clutch body is loose on the crankshaft, the resulting vibration can make the seal leak, and is probably the cause of your grass deflector screws coming loose too. It could also have broken the seal between the gasket and the metal sealing surfaces.
The torque setting for the crankcase cover bolts is 85 in-lbs, for this series engine.

Hi BB,
My dear wife managed to find the receipt for the mower when we purchased it in February 2004, and it is in fact a reconditioned Scott Bonnar 45. Attached to the receipt is the operating instructions for the Scott Bonnar Model 45 Series Reel Mower. So I reckon you are spot on with your photo, repainted Rover red

regards

Tim

Better photo of the rear rail without the grass, but still no ID plate

I reckon the frame at least is a Rover 45. It has the 4 holes in the rails where the black plastic cover fits over the clutch cone and screws to the frame. Im no expert but dont think the Scott Bonnars had the covers fitted. I could stand corrected though
cheers Ross

Hi Rossf,

I reckon you're on the money as those holes are a dead giveaway and as such then the motor may still be the original unit fitted. If Tim could get the code of the motor cowling then we'd get an even clearer picture to what this one may be. One way or the other the chassis ID has been removed as they were one of two designs either a riveted ally plate stating Rover Australia or a metalised sticker which was used on the very last Rover Reds as is the one pictured with the rearward facing clutch lever. They also had the 75db noise rating sticker at that point stuck on to the rear rail,

Cheers,
BB

Hi Tim, BB and Ross,,
I think we all agree that it is a Rover chassis. I believe it also to be a 'bitza'. To prove my point, no Rover red 45 had the cotter pin inner clutch half....you can even see the old Scotty green under the flaking black paint.
I don't believe the engine to be original to this chassis, Keith would have selected one from his reconditioned lot and bolted it on....

But for all of that....we have gone seriously off topic...this thread concerns cutting and clutch probs...We really should get back to that.

Thanks Deejay, great to see the enthusiastic responses but I want the mower to cut grass! You have already given me some advice on cutting adjustments, Gadge has given me some tips on the motor, and I had a question on what clutch parts do I need to replace the cotter pin set up

Regards Tim

Hi Tim, you will just need to purchase an inner clutch half and the 2 grub screws to suit. Just check the diameter of the engine PTO shaft before you order the part, as there are 2 clutch halves sizes available, to cater for different engine shafts.
Please see our video HERE for instructions on how to remove the engine and clutch.
Once you have it removed, please post some pics of the inside of the clutch, we will need to check the serviceability of the thrust bearing and the clutch cork on the outer clutch half.

I can't believe that we are going back to clutches as that was discussed in the first few posts that Tim and I exchanged regarding not using a clutch half that had a captive cotter that was coming out and that the body would be flogged out, thus requiring a new one to be purchased.

Hi BB, this is what sometimes happens when threads go seriously off topic....It is a good idea to check the subject of the thread occasionally to make sure that what we post is in the bounds of the subject matter.
We all got caught up in trying to sort out what this machine was, instead of helping Tim get his machine up and running.

As nobody has yet listed these, now that we have 'returned to our muttons', the bits that Tim62A will definitely need are:

5/8" crankshaft clutch body

OR

3/4" shaft clutch body

PLUS

Clutch body key
2 off 'clutch body set screw'
clutch cork lining

Possibles:
Clutch thrust bearing
clutch body screws

All good guys, thanks for your help. I will order the parts and tackle it after Christmas. I think I will stick with the existing motor for now

regards

Tim