OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers SB Model 40 - 12 Volt Cordless Electric

Hi Everyone,

My dear old Grandfather has been kind enough to donate to me an old lawnmower for my new house.
It arrived at my place today and I've never seen anything quite like it. I've seen 240v electric mowers before but never one that runs off a battery.
Luckily it still has some clearly readable badges and labels on it so I was able to begin searching for information on it. I arrived here.

From what I can read it is possibly a Model 40?

Cosmetically I'd say it's in reasonable condition given it's age... I assume it's quite old?
I pulled the battery out of my car and hooked it up to the mower. I pulled the triggers and away it went without any hassels.
The lawn was quite wet so I wasn't expecting too much and I would think the blades could do with a sharpen.

Like when any guy fiddles with stuff there is always parts left over. As you can see from the photos there is a bracket without a home. I assume it bolts on where the handles join the base of the mower, am I correct?
It is also missing the catcher. Does anyone know if a catcher of a differnt model will fit or can be made to fit?

Regards
Dan

Hi dansblackcat, and a warm welcome to the forum. It's great to have another Scott Bonnar owner on board. We all like to learn new things and tinker here, and this particular machine is no exception.
Just when I thought I have seen all the models manufactured post 1950, here we are with a model I never new existed. I have never heard of, let alone seen one before. This is a rare beast indeed!
You are correct in your assumption, it appears to have been based on the Model 40 chassis, there may be a model number stamped on the brass ID plate riveted to the back of the battery charger, that may pin it down. It appears to be a 14" cut, and if it is part of the Model 40 family, it would have been manufactured around 1960. So it is an oldie.

Re: the bracket, I cannot see where it would fit or more importantly what purpose it would serve.....my only thought is you may be correct, it may fit where the lower handle-bar attaches to the mower; so that the machine can't be tilted so far backwards.... maybe to prevent battery acid from spillage through the vents in the cell caps???

Parts are extremely hard to come by for a Model 40, and in particular the catcher....a Model 40 is the only one that will fit your machine particularly because of the way it attaches to the machine....the catcher hooks fit into the two vertical slots just in front of the grass deflector.
I sold a Model 40 in very good order because I couldn't beg, steal or borrow a catcher for it.
It is a rare and unusual machine....well done and a great score!

Hi Deejay and thanks for the reply.

If you have never seen or heard of one it's no wonder I couldn't find any reference or pictures of it on the internet.
I gave the ID plate a light cleaning and it is now quite readable. Model 40 14471

What you say about the bracket makes sense. It would be easy to tip the mower at such an angle that acid pours out everywhere.

Not being able to get a chatcher wont be the end of the world...maybe one will pop up one day.
EDIT: The catcher has been found in the back of the shed

My Grandfather rescued this mower from his neighbour who was going to put it out for roadside collection. Thankfully it now has a new home.

Hi again, that is great news about the catcher....and we have pinned down that it is a Model 40. I also notice the original colour underneath the black....the machine would have been SB aquamarine (solid colour, not hammertone) and you will have a great sample (if you are going to restore it) underneath the ID plate.
We're glad also that it has gone to a good home.

Hello again.

Here is one more photo. It shows the electric motor and also what I imagine is the original colour you were referring to?

Hi again dansblackcat, actually no it not the colour I was expecting, but it is the standard hammertone paint that Scott Bonnar used on the Model 45.
Thankyou for posting the pic. Are you going to restore it?

I think I will try and have a go restoring it once I move into my new place.
Given the fact that it still seems to operate like new and does a good job cutting the lawn, a restoration will/should only involve restoring the panel and paint?
For reference purposes it would be nice to find a picture of what one would have looked like new.


Where is the best place to get the paint you have mentioned?

It would be useful for the archive to post a wiring diagram, or at least enough pictures so we can trace the wiring of both motor and battery charger. The motor's identification plate would also help.

Hi Grumpy,

There is very little wiring, pretty much just the cables running from the battery to the motor via the cable operated on/off switch.
There is no battery charger built in. The socket in the 3rd photo of my original post is just a low voltage plug (32v max - commonly used for car fridges). Maybe the movers were sold or supplied with a charger back in the day.
For now I am using a C-tek charger to properly maintain my deep cycle battery. I have a small solar panel that I am going to mount on the shed roof to keep it charged.

Here's a few more photos-

Thanks for that. The electric motor looks generically similar to an automotive starter motor. At the opposite end of the motor from the output sprocket in series with the ground side of the motor, there is a spring-loaded device that looks as if it may be a thermal overload, to keep from destroying the motor or battery if things get stuck. Can you confirm that is what it is for?

Hi grumpy, that device with the spring is a Bowden cable operated on/off switch...ie. squeeze the handle (or whatever procedure) pulls the centre (of what looks like a solenoid) and makes contact and motor runs...let it go and the spring pushes the centre collar back....motor stops.
If you look at the very first pics posted, you can see the cable enter the box, with adjustment similar to that of the Model 45 roller clutch.

Thanks Deejay. It looks as if the original battery charger (apparently a remote unit that stayed in the shed beside the power point) is no longer around? I'm guessing it was just an old time automotive battery charger: a simple transformer-and-rectifier circuit with no regulation or output voltage sensing. It would be good for the archive to get details of it, whatever it was.

Hi grumpy, considering that we have never see one of these battery powered Model 40's on this forum and I had never known that that they even existed....they don't appear in any early advertising material that I have seen....I think that finding a pic or info on the charger will be a bit like finding a Wipac "Magister".....like hens teeth.

I will, however, make some inquiries in Mildura and Adelaide to try and fill in the gap....Just maybe......

Not a Scott Bonnar.
I've attached a few pages from a Ransomes battery electric mower manual from 1962 for interest and comparison with the Scott Bonnar Model 40 battery electric from the same period. I guess Scott Bonnar would have produced a similar manual.
Regards,
Grant.

Yeah that's very similar to my mower but looks to have the charger built into it.

I'm going to ask my Granddad if he can see if the guy he got the mower off still has the original battery charger and/or the manual...ya never know.

Hi Dan, that would would be perfect result if you could get the original charger for it mate, or even some printed info.
Looking forward to the result of the inquiry.
Best of luck,

Well Xmas has come early this year for one lucky little mower.
Restoration has finally begun and I decided to even get her a little sister to play with.

Hi dansblackcat, and welcome back to OutdoorKing. it's great to see the resto started and your new addition.
If you can supply us with the complete string of numbers stamped into the air cowling of the Briggs and Stratton we can give you the date of manufacture of the engine which will then give us the approximate age of the edger.

Hi Deejay

Here's a quick picture of my progress so far. It's looking pretty good. It's a bit greener in real life, I think the fluoro lighting made the image a pit pale.
Also there's a pic of the tag from the edger. It has a 2HP Briggs and Stratton engine.

One thing I have notice is that now I have had the blades sharpened it that when I adjust it to where it needs to be the chain is extremely tight, no slack what-so-ever. There is no tensioner for the chain like I've seen on some of the other models. The adjustment is made my moving the cylinder. Would you suggest just adding another link or two to the chain?

A History Record is now available for the Model 40:
https://www.outdoorking-forum.com.au/forum/u...del_40_-_12_Volt_Cordless.html#Post38204


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