OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Scott Bonnar Model 40 - Petrol

Hello everyone, first post so be gentle

I have just got a SB 40, 14 inch with what i think is a villiers motor on it due to the fact it has villiers on the air filter shroud.
I cannot find any pictures on the net with the same motor set up as i am trying to find the age out on it.
I want my kids to strip, and rebuild it back to as close original as possible but without the pik's i am a little stuck.

Can anyone help?

If you can post a picture or two of your mower's engine, there is a good chance Deejay (the resident SB history buff) will be able to help you find a suitable internet site when he gets back from a short vacation he's on at present.

Fingers crossed see if this works, a bit blurry because the boy took at part of the project.

The engine looks like it could be a villiers mk15 about 147cc, 1.95bhp @ 2,800 rpm, with 47mm stroke and 63mm bore

I think this engine is a villiers 150cc lightweight as it appears
to have an alloy cowl and the f15 engine had a pressed metal one.Both engines have the same bore and stroke.villiers list as
supplying scott bonnar the 75cc and 150cc lightweight engines.
sorry but i dont have any information on the dates rhey were made.

Thanks guys, yes it is a alloy / ally side cover, and the pull cord bolts to this. Has scott bonnar grips too. Villiers on the carb and air filter housing.
The kids want to tear it down, but i want to make sure i know whats what before stripping and painting.

Speaking of painting, is there a paint code for that green and red?

Thank you to a man in Adelaide for some wonderful information, Cheers mate your a superstar.

So he sorted you out with what info?

I bought a SB sticker off ebay, the seller saw the post on here and sent through some information dating the mower to the 60's. And he also included a copy of a handbook with operating instructions and spare parts diagrams.

I just thought he deserved a huge thank you for going the extra mile or two.

Witht his info We are now thinking 75 cc, and i keep searching the net for one with an identical fuel tank, unless of course the old one rusted out and was replaced with this round item as this is the only real difference from the diagrams, and maybe the pull starter.

hello mik, the fuel tank on your engine is the right one for the
150cc engine.the 150cc has a screw in oil filler and dipstick,the
same as yours but the 75cc has a needle type dipstick which is
located on the top of the crankcase cover, see your parts book.
The 150cc engine should have a on/off switch on the alloy cowl.
the best way to be sure if its 75 or 150 cc would be to remove the head and measure the bore.regards john

It has the screw in oil cap rather than the dipstick, i did notice that, and the carb is just ever so slightly different to the ones in the diagrams.
There is no kill switch on the cowl, you have to earth the HT lead on the head.
I will get the head off this weekend, good excersise for the kids to measure the bore and stroke and work out the cc. I have a feeling it could be a 3 Ltr motor by the time they finish, but it will help with maths at school for volume Etc.
Once i know i will post it up.

Thanks once again people.

Head off today and it looks like 75cc

51.5 bore
34 stroke plus piston dome

r x r x Pi x S

By reading other post's it looks like the paint will have to be matched, just need to get the kids to schedule the strip down.

Hi Guys, I'm new to this forum and I also have a very simular mower. Mine is in pieces awaiting a rebuild. A couple of Q's. Are gasket kits still avaulable? Is there a manual for teh engine, the Carb and of course the mower?

Hi TwoArrows, and a warm welcome to the forum. It's always great to have another Scott Bonnar owner on board.

Unfortunately, info on the SB Model 40 is pretty thin on the ground and I can't be much help to you. However if you scroll back to post # 18974 you will see that Mik has a manual and spare parts list for your machine. Just click on his username, scroll to "Send a PM" and post your questions, he may be able to send you a copy and supply gasket info.
PLease let us know how you get on...

A History Record is now available for the Model 40.
https://www.outdoorking-forum.com.au/forum/u...DEL_40_-_14%22_Reel_Lawnm.html#Post84251


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