OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Can Anyone identify this mower for me??????

Any help at all with this mowers indetification would be great.
Thanks

Hi 78rusty, and a warm welcome to the forum. It's always nice to welcome another Scott Bonnar owner.

What a ripper of a machine you have there, and in such nice condition.
Yours is a Scott Bonnar Model 33, first introduced in 1960 and manufactured at Thebarton in South Australia. Inside the chain case you should have a combination of belt and chain drive.
Once again 78rusty, to OutdoorKing.

Thanks Daryl.
As you can see by the attached photos I have cleaned up the compliance plate but it doesn't say year of manufacture.

Also in the second photo there is a plunger style plug under the fuel tank. Is this some sort of choke?

Sorry above the fuel tank.

The control circled in yellow, which you pull out with your finger and thumb, is the choke. In the picture, the engine is on full choke. The control pushes in until the painted parts touch each other, with the slide in between completely concealed.

The most practical way I have found to use that choke is to apply it fully from a cold start, then pull the starter either once or twice so that it starts, chugs, rich-loads and stops. Then I push the choke right in, and pull the starter once. It always starts and runs perfectly then.

The reason for using that chainsaw starting procedure, is that I've never been able to get to the choke and push it in before the engine stops. If you are a lot quicker than that, you might be able to get there in time.

After running for a minute or so, you can start and stop the engine without needing to use the choke again until the next cold start.

If you post the three groups of numbers on the cowl right above the muffler, we can tell you the date of manufacture of the engine.

Hi again 78rusty, Unfortunately it is impossible to give an exact date of manufacture of a particular Scott Bonnar machine, as the serial numbers did not run sequentially....and the date was not stamped on the mower anywhere....
However, I can tell you that production of the SB Model 33 had ceased by 1966....so it was a 6 year run.