OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers SB45 - Rescued from certain death

Hi All my name is Peter and a few days ago I rescued a Scott Bonnar 17 inch reel mower from a friend who was about send his mower to the local tip , lucky for me he gave it to me and now I am hooked on scottys , I have disassembled it read for restoration , sadly as I was trying to undo the nut holding the magneto / flywheel on I broke the thread off the end of the crank , now need a new crankshaft , straight on to ebay and found about 10 NOS cranks for sale all with different part numbers , my question is can someone tell me what crank the HK25 series 2.5 HP Kirby had , yours Peter

Hi Peter, welcome to Outdoorking.

Parts and part numbers for Kirby-Lauson engines can be a bit challenging. You probably know that Kirby imported most of the parts from Lauson in the US then did final assembly, plus sourced some bits locally, to avoid import duty on those engines. However Kirby mixed-and-matched features from the Lauson model range so his products tended to be hybrids of a couple of Lauson models.

Here is the Lauson Parts List that applied to the engines Kirby was mixing up:
http://lausonsmallengines.com/literature/specifications/tecumseh/H.PDF

As you'll notice, when it comes to crankshafts the parts list tells you to refer to Form 690157 dated February 1958. I don't know how you would get hold of that form, but it probably includes lots of different part numbers for crankshafts that only differ in details that don't matter to you.

Be sure you select a crankshaft with a stroke of 1 3/4", which means it will be for an H20A, H25A, or HB25A. The H30 engines had a longer stroke. Note that Kirby-assembled engines were identified as HK instead of just H.

Incidentally, you might be interested in this thread:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=37736#Post37736

Hi Grumpy thanks for the info ,Parts and part numbers for Kirby-Lauson engines can be a bit challenging, is an understatement , I can't believe how simple the little kirby engine is when compared to a late model engine of the same HP rating . anyway thanks again , yours Peter

Hi Peteskip,
Whilst you have your machine stripped down for painting, have you completely disassembled the machines chassis frame?

Hi Deejay yes I have completely stripped it down and it all looks good I will be replacing all of the bearings ,and anything else I can find that needs to be replaced , I will post some photos as I go through the restoration , There is one question , when I removed the rear drive rollers I noticed the outer ends of the rollers were painted light gray ,would the rollers have been all gray when it was new ?
yours Peter

Hi Peter,

I'm not sure on that one mate, my Model 45 is a later twin rail model and the rear roller is not painted at all.

Hi Peter, there is some evidence to suggest that the rear rollers were painted light grey on the early 45's. Here is a picture. Regards, Michael

WOW What a photo , I was thinking about getting the rollers powder coated in that light grey but wasn't sure what color they were , I guess grey it is , thanks Michael I guess there are others out there that would be interested to know what color they were , is that a scotty been restored or is it a photo of one when it was new Yours Peter

Hi Peter, it's a photo from a 1968 Scott Bonnar brochure which introduces the Model 45. I've powder coated the rollers on my own 45 resto in this colour but I must admit I've had second thoughts as to whether is was the right decision.

Hi Rolla,

The rear split roller could also look grey as SB did use aluminium units as well not just cast iron. I have examples of both on hand and asked the question in an earlier thread about their application, but it seems they were only used on 14 inch units but the reasoning is still unclear as to why two different materials were used.

Cheers,
BB

Hi BB and Rolla,

The 14" Model 45 was the baby of the family, mainly for use on small lawns and maybe weight was not a consideration.... whereas the 17" and 20" machines were for use on medium to large lawn where weight was needed for rolling of the mown grass and cast iron was the preferred material.

As usual with most things Scott Bonnar, it will probably remain a mystery.

Hi All I have just received a shipment of parts from our favorite supplier and it all looks great , I have sent some parts away to be chromed and zinc plated should be back soon , I am going to soda blast all of the parts that need painting ,I have had a local paint shop match the paint (hammertone green ) I have had the drive rollers sand blasted and powdercoated in light grey , all in all the restoration is going very well , the only thing left to do is make a decision about the engine , to restore the original engine and reinstall it or put the restored engine away and replace it with a new up to date engine ,anyway I'm loving it , I have spent most of my life restoring cars that take years to finish ,this is the first time I have done something so small , I can't wait to get my hands on another one .

Hi All well I have just received a shipment from the elecrtoplaters and it looks great except for the front roller it was supposed to be zinc plated (blue) but came back chrome plated , even though it looks very nice I think it will go rusty over time so it gone back to the electroplaters , anyway the restoration is comming along fine , I did go for a new engine its now got a 3HP B&S bolted no it , I love Ebay .Photos will posted soon .

Hi All i have finally finished my Scotty ,Its only taken a year Sadly I couldn't get the kirby to fun so i went on good ol ebay and found a new B&S and it runs great . I will post some photos as soon as I find out how .
I have a friend that owns a Morrison Olympic 24" reel mover and the nylon gears in the roller have broken he has taken it to a "Mower Center" and they told him its beyond repair and buy a new mower , I say is is repairable and I am going to have a go but when he got it back it has been completely dismantled , Does anyone have a workshop manual for one .
yours Peter

Hello Peteskip!

We would very much like to see the Briggs powered machine.
This is how to post photos: HERE.

The Morrison Olympic machines are now the Masport Olympics.
Given that this is a 24 inch, you won't be speaking of the nylon reduction gear
(used in some smaller models), but a nylon differential bevel gear.
These would be the same as used in the Victa Imperials, I think.

It may be that the current Masports also use this nylon gear arrangement.
We have operator's manuals and parts list for the Masport Olympics.
We would need a photo of the machine and inside the chaincase to help out.

Hope this helps.
------------------------
JACK.

Hi all and what a grate page for info ,I too have been bitten by the SCOTTY bug I was lucky to find a hk25 at the tip (Ballarat ) since then I found this page and another SCOTTY I think it is a 33 it's a lot smaller than the 25 ,I have notice there is some very switch one people out there so if possible would like as much feed back on the 33 if that is what it is ,,have put some pics up above this and yes I did it wrong sorry all

Hello Buddeyboy

A warm welcome to the ODK forums!
I hope we can be of help here.

So you have a Model 33 and a Model 40.
So, what are the plans?

The Model 33 is the precursor to the famous Model 45.
It's a great design, and still a very good performer (by modern standards).

The issue, now, with the Model 40 is the primary clutch - the rubber drive
is not available, and no solutions have been proposed for when it wears out.



Hope this helps.
------------------------------
JACK

Thanks, jack for the reply and info
Plans for the 33,are a basic rebiuld motor is complete (no compression do to vales,job done all good now) I picked up the 33 in a farmers,padock a tractor ran over it so it needs some panel work and relinement sound wors than it is
A lick a paint some detail then back to work, what it was ment for (love the sound off a motor running)
The 40 I got at the tip it's all there other than the catcher I think ,still has the original hand grips with logo on them and still had leaded fuel in it,choke 3 pulls and of to work ( that's a first for me )
I have collected quite a few motors from the tip (boat,mower, chain saw ect anything old or I can Carey out with me and never one that started ,lucky for me as I would off had to leav it behind if it didn't start
Thanks agian jack