OutdoorKing Repair Forum Forums Finding and Swapping Rare Finds & Donations ARCHIVE: Scott Bonnar Model 22

Hi Guys, Wondering if anyone knows much about this scotty and its engine, I would love to be able to work out how old it is, and what capacity the engine is.

Of my recent skip find, this one is the closest to complete, all it needs is the blade disk, and for me to bolt down the engine.

If anyone has any information on this machine, Its Engine (JAP), Fuel mix, or where I may find a blade disk, That would be greatly appriciated, I would love to see this one going again.



EDIT: I just remembered, It is also missing the fuel cap, and tap, if anyone has pictures of what these should be, I would be very happy to see them. The fuel nipple on the carby has also snapped off, but i beleive i have the part to fix this.

Don't have a lot of pictures of it but here is what I have.


Sorry man that's all I have on that one.

Thanks Jeffery, That looks a bit like the old brass Victa Taps, so I will see if one of them fits for now, And it gives me a rough idea for the cap.

If anyone can shed some more light that would be great!!!

I'll pop up a few photo's of the blade boss tonight, If anyone can help me locate a blade disk, or even just show me what one looks like, that would be great!

This little JAP engine has good spark, and great top & bottom compression, the carby is sound, and I have nearly finished replacing the fuel line, tap, nipple & cap, so once i pop a disk on, I can start looking into getting this one running!

Heres a couple more pics!

Hi Ty, unfortunately mate information is pretty thin on the ground with early Scotty rotaries, is there a model number anywhere on the machine...most Scotties had a brass plate attached somewhere on them.
If it has a number I can begin some research for you.

The cable will be suported on the handle, and when i fix up the cable, witch may need replacing, I will have a look into a spring, as you have menttioned, as this mower has a flip over handle, that can fold flat to get under bushes, and such low angles will pose a risk to the new cable.

The paint job was done by another restorer, who after restoring, and failing to sell this one, threw it in the local scrap metal recylclers bin, the red paint on the intake is only on the access plate, the intake holes are in the other side of the intake, and are not painted.

I'll pop up a photo tonight of the carby set up, you can make the holes out in the 3rd last photo, on the back of the intake 'Head'.

And I'll dig up the number on that brass plate, it is there, I forgot to get a good look at it, I'll see if thr number is visible in any of my photo's here, if not, I will look at it tonight!

This is the best I have right now, fairly useless, but enough to verify the originall scotty plate exists, I'll post the numbers tonight!

I'm very excited about this one, it is very close to complete, a few bolts, cap tap, line and a blade disk, and It will be ready to try running!



Also, here is the best pick i can find at the moment of the blade boss, anyone think they may be able to help?




ALternativly, would it be possible to alter a different blade disk to fit?

What is wrong with the blade disk you have, Ty? Original is always best. If it is just a matter of getting a blade disk to fit, it seems better to alter a disk than a mounting boss because it keeps a bit more of the original mower. You can hope to get a proper disk later, or at least a photo so you can make a different disk look like that one.

My aim is to alter a disk to fit this boss.

This mower was discarded by a collecter in QLD when he was unable to sell it. I pulled it from a skip, without the blade disc, so untill i work out what is original, I will need to use something else to get it running

I will have a look at a few blade disks I have when I get home, I think a briggs might be a reasonable starting point!

OK, I make the label out as:

SCOTT BONNAR LTD
AUSTRALIA
Serial No. 22 01710

Here it is, as well as a better pic of the blade boss.



Also, here is a better look at the air filter grumpy, the paint is clear of the intake holes:



And here is one without the paint, you can see the circlip that holds it shut.

You are quite right Ty, I had leapt to the conclusion that it was a straight-flow air filter and it turns out to be an indirect flow type.

Hi Ty, I have checked my Scott Bonnar info but unfortunately most of which covers cylinder mowers, but there is reference to a rotary called the "Spin-Cut" being produced in 1958. It doesn't mention your model 22, but the timeline seems about right. Scott Bonnar also used JAP engines on the 14" Model 40 "Terrace" mower and they were first introduced in 1960.

It is a shame that the fuel cap is missing, these are sometimes hard to find for vintage British engines.

Thanks for that Darryl, I didnt realise that 22 was the model. I will mesure the deck tonight to work out the width, it is only a little one though, Whitch is proving hard to find a disk i can adapt to, I'll keep diging though.

I'm going to make something up to suit the fuel cap for now, I imagine it will be a while till the right one presents itself.

Grumpy, The Lawncub has the same one (its the non-painted pic) however in some pictures I have of other lawn cubs, there was a straight through one used, i think the pictures are up in the lawn cub's thread.

Here is the blade disk i have sound, that I will try to alter to fit the Scotty 22.

I am a little worried it will be to wide, so I am thinking of cutting down the blades, rather than trying to take metal of the edge of the disk.

I will be balancing my work before attempting to use, and I will see how much alteration will be needed and report back tonight.

I have a feeling it might be, bit i cant recall what it is off, and i have not pulled it down off the shed wall to get a good look at yet, just noticed it up there as i was leaving thismorning, and though it might be a good place to start, as it seems to have a similar bolt pattern.

Looks like it could be a rover disc on the wall.

Being a side throw mower you would only need flat blades on it.

A bit of a tip, if you need the disc to be smaller diameter, get a set of new blades that suit do all the measurements, bolt them all together clamp them in the vice and cut them all off at once. Instantly ballanced.


The boss is a 3 bolt pattern. Regular rover is smallest. Masport is a bigger spread (and 6mm bolts rather than 1/4" UNF) and i thnk theres an in between. Then the wide cut rovers are bigger, but they are huge by comparison.

You can buy a universal blade disc that will take different type blades, and put baby bob blades on it.

Older rover side throws have a small disc., smaller than the regular 18" disc. Then longer blades.

You can also use the smaller disc on the wide cut rovers with Honda blades.

Ive had this blade disc stuff do my head in over and over. lol.

Thanks for the info Bob.

I'll definaly use your cut-all-at once trick, and I may have a few of the other disc's you have mentioned, to try and get a match.

Where can I find a universal disk, if i cant get one to suit?

Im sure bruce will have the universal discs in the shop.

Most mower joints carry something. Because of all the different variations they may not have what you want but may have something that can be made to work. You might also get that what model and whats the engine number blah blah as well.


It will depend on the PCD that the bolts are.
If you have other engines there, looking at the blade boss, reguardless if its a round or 3 lobe type one, the rover bolts are close into the middle (the hole for the 3/4 shaft) the masport ones are closer out towards the outer edge. Some have it stamped on them, rover or masport. And im sure theres another pattern thats in between. Its a pain because between the three patterns theres less than a half a hole difference.

I cant comment on the super swift as i have not had much to do with them. Or in the case of the Vulcan and Bob i did have, ive been mixing and matching bosses and discs. Im sure the vulcan had a universal disc on it with babybob blades. Ive just got a tub full of bosses, so i grab whats going to work with the disc thats going to work.

I assume its an 18" cut.
I would aim for the universal disc that will take the babybob blades (shorter than Victa blades). They are easy to get and can be fitted up to the universal disc. Or you might be able to get Victa utility blades to swing under it. Thats provided youve got the right drop.

So it will depend on the PCD and how much drop it needs in the disc. If its anything like the SB720 (different boss to that one) they have a dished disc and step down blades.


Given that i have had to do some mixing and matching, i kept the nose off a stuffed crank. I can insert that into a boss, bolt a disc on so its concentric and then run a drill down through the holes in the boss from the top to line up a slight miss match. Or some mowers had a big washer with the 3/8 centre hole and the 3 little ones. That can be bolted up and just use a small file to oval the holes out a touch. Then use good washers on the bolts. Ive got some big washers here, i think the centre is 10mm, ive also set those as mentioned above with the boss and crank snub and drilled them usually to bolt on over the top of the center of a blade disc that has had the holes flogged or ovaled to give it some extra strength/security.
It might all sound a bit dodge, but i have a tendancy to over engineer things, if i do not think it is 100% safe and i wouldnt be happy to use it and stake my life on it there is no way i would sell it or even give it to someone else.


Looking at the pictres again i dont think the rover disc will fit. If the nut is 9/16 in the centre, the pattern is bigger than the rover. I would be looking for a universal disc to suit a masport. Even then you may have to find and use some of the step down SB blades.

Whats the distance from the lower edge of the deck up to the face of the boss??

I'll have a go at it tonight with the mesure,and get all the mesurements, thanks for your help, hopefully I will be able to get this little one up and runing!

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