OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar 45 Chain Adjustment Slide

New to this forum and have posted this previously in the incorrect topic thread. Sorry!
Im doing a bit of maintenance on my Scott Bonnar 45 and have found the Cutter Chain Adjustment slide needs replacing. I have chased around a few lawn mower repairers around me and no one stocks this part anymore. The original part number is 451258. This is the round nylon adjuster slide.
Does anyone know where I can possibly get one of these or know of a way that I can retro the new version to fit my mower.
Thanks in advance

Hi Gatty7,

You should be able to undo the nut and rotate it and get a fresh part of the adjuster to come in contact with the chain.

Cheers,
BB

Hi BB

Have this done this already in the past and the adjuster is well and truly past its used by date.

Hi to Gatty7 and BB,
Would it be possible to post a large pic of the machines chain case so we can see whats happening in that area? We then can give you some advice as to a fix for the problem.

Hi Deejay,



The issue I am having is that the chain keeps coming off on every mow. I have previously been rotating the slider but it has got to the point where there is too much slack on the chain.

Cheers.

Hi all and welcome back home DeeJay,

Honestly the chains and sprockets are past their use by date thus you cutter chain will continue to fly off more and more. You will have to replace the cutter sprocket and the transfer shaft sprocket along with the chain.

I'll have a closer look at the photos and give some more info when I get back home.

Cheers,
BB

hi gatty7 . even i can see the chains are dry , large sprocket on the reel is BADLY worn so yes the chain will jump off . its looks as though it unevenly worn too so even worse !
as all know i am not a reel mower guy (too much like hard work for me) but i did use when i hadto service one or two was TAC2 on the chains , a good sticky lube simillar to bike chain lube but i did use it on hoist posts when i was on the tools and stayed in place for ages easy to clean too .

roller is way too worn to be of use now . BB can tell you for sure or deejay too but maybe the block type of thing ? replaced the rolloer and far as i know still readily available too . just sort of a rubbing block not a roller but still needs to be lubed well and cleaned often .

sorry for jumping in but even im not a 45 fan i can see some problems there

, Dave

Hi Gatty7, BB and vccomm,
Both BB and Dave are spot-on with the diagnosis...the worn primary chain has stretched beyond its limits; the double front sprocket is clagged completely and the nylon chain adjuster has reached the end of its tether.

(1) The primary and secondary chains need to be replaced.
(2) Replace the double cutter sprocket
(3) Replace the nylon adjuster....this may be hard to come by...I will do some research for you as will BB I'm sure...
(4) Clean thoroughly the whole chain case and re-lube the chains and sprockets....this is important mate, to keep your machine in good order.

Thanks guys for your help I'm on to the new chains and the sprocket, but if you could help out on the nylon adjuster that would be appreciated.

Cheers

Hi Gatty7 and DJ,

I shall check up with a good supplier I have but I'm not expecting a good outcome. I've never seen such a badly worn Series 1 adjuster. I'm thinking of how to retrofit a Series 2 unit on while still retaining the chain case mounting bracket as the series 2 machines have the chain case screws vertically affixed to the chassis and not horizontally to brackets. I'll have to have a good look at both machines that I have here and see if this can be easily done without too much mucking around.


Cheers,
BB

Hello Mod BB, Gatty7 and Admin. DJ

This is an important topic - the replacement of the round adjusters.
I don't see the later block adjusters as being the best option,
given the quite different designs.

Gatty7, Mod BB is the forum's 45 expert, so I am confident he will
come up with a solution.

Cheers and welcome to the forums.
---------------------------------------
Jack

p.s. that's a real flogged reel sprocket!
I don't think I have seen one that bad. It may be that the chain was
over-tensioned to compensate, thus destroying the tensioner.

Hi Mod CyberJack and Gatty7,

I would have to say that Jack is spot on there regarding the over tensioning so that the chain would still drive the cutter. It's definitely in the top 10 of flogged out parts I've seen.

I'm still awaiting a call back regarding the availability of getting a Series 1 tensioner.
As soon as I hear something back I'll let you know Gatty7.

Cheers,
BB

Hi Gatty7,

Well I have an answer for you which I gather you're not going to like.

Firstly they are not commercially available at all on the open market, but and here's the catch, my supplier has had them custom made up in the past and he makes nothing on them at all, more so just supplying a service that otherwise isn't available that supplements the core of his business, lawnmower repairs.

The cost of a replacement unit is $50 (ouch) and as far as retro fitting a Series 2 unit onto a series one, that's not possible without a bit of rework on the black series 2 unit so it fits in place and does the job..

If you want to proceed I can organise it for you and rest assured I'm not making a cracker on it, merely just helping you out.

Cheers,
BB

.

I was faced with a similar conundrum when I rebuild my solid deck 20". The original adjuster was quite flogged so I ordered an extra series 2 adjuster as they are dirt cheap and thought I could see what I could do with it. It needs to be re-drilled to 3/4" (90% certain of size) and the small plastic slide guide on the rear buffed off. Apart from that you just need to align it correctly as the series one tensioner rotates rather than moving on a straight plane.

Has not been an issue for me in 18 months and I mow a lot!

Hello SimRice, Mod BB and Contributors

I think Gatty7 - and Mod BB - will be very pleased.
This seems like a nice, elegant and simple solution.
I was concerned as to how the bracket might be retained.

Thanks to SimRice for the idea, instructions and photos.

All very clever.
----------------------------
Jack

Hi SimRice,

I did think about doing that in the first instance, but now you've proved that it does work, so I guess that will put the $50 idea into the bin.

Cheers,
BB

The tensioner on my 33 has been modified in much the same way except the guides on the rubbing block are still there. The chain link is a bit of a squeeze through the guide but it seems not to bother things



I bought the same black block as above to see if it fits better, good luck !