OutdoorKing Repair Forum Forums The History Forum The Old Soap Box RESPONSE to THE ARMY MOWERS - early 1940s

Just a bit of info on these Buzacott [also sold as Rosebery] hopper cooled single flywheel stationary engines.

I did an overhaul on a 3HP Buzacott as a project in an 'Automotive Practices' subject in secondary school, back in the '70s. The teacher wanted to set one of these old open flywheel engines up with a flywheel brake, to demonstrate measurement of horsepower and torque using a spring balance! Our family business included farm machinery sales, and we picked up one of these engines from a customer's farm for the sum of $5, to donate to the project.

These were actually built as a kerosene engine, with a very primitive floatless 'suction valve vapouriser', not a true carburettor. The main tank was for power kerosene, and there was a small 'starting cup', with a pivoting cast iron lid, mounted off the side of the carby. That's the type fitted to the green engine in CyberJack's first post, and the fuel tank is in the original position there, for suction feed. The higher tank position would have been necessary to use a gravity feed carby.

To start the engine, the main manual needle fuel valve at the venturi was closed, and the cup filled with petrol. Then you swung on the [detachable] crank handle to get the engine to starting speed. You made sure you didn't wrap your thumb around the handle, in case of a kickback!

It was then a matter of letting the engine run until it started to misfire as the petrol ran out, and then opening up the needle valve until it ran smoothly. By then the cast iron inlet tract would be warm enough to vapourise the kero; it was an en-bloc casting with the exhaust outlet.

They were a governed engine, with a centrifugal governor controlling the magneto timing. The governed speed range was in the region of 750-1000 rpm. Speed control was by adjusting a preload screw, on the external governor spring.

There are a couple of pics with the bits labelled HERE

As CyberJack says, these engines had very poor power-to-weight ratios; they were built for longevity and reliability in rural conditions.

Hello Mod. Gadge,

Well, that's most helpful for us understanding just how 'foreign' these engines
were to lawnmower engines. The Scott Bonnar must have been a real 'handful' to manoeuvre,
and certainly not suitable for anything but slight inclines.

Global Mod. Grumpy has pointed out to me how the high centre of gravity and the
weight would have made these machines particularly not suitable to anything but
dry ground. I guess the story is a real case of 'making do' with whatever we could
manufacture in war time.

I have a potentially dumb question: was kero used because it was cheaper, or was
it because gasoline was hard to come by at times?

------------------------------------
JACK.

Not a dumb question at all! It's one of those 'forgotten knowledge' areas, these days.

Power kerosene [as distinct from 'lighting kerosene'] was indeed cheaper than petrol, when it was available.

There were two reasons for this.
One was that it was a less highly processed fuel; just a 'straight cut' distillate of crude oil, with a boiling range in between the lighting kerosene and petrol fractions. Treatment to remove gum-forming alkenes wasn't used, nor much in the way of additives to improve shelf life/performance, as were used in petrol even back then.
The other was that the taxes applied to fuels for road-going vehicles were never applied to kerosenes, just as they weren't/aren't applied to 'heating oil' distillate and Aviation fuels ['Avgas' aviation gasoline, 'Jet A1' turbine fuel] in later days.

Kerosene was much easier to get in wartime, as it wasn't severely rationed in the way petrol was.
Availability was much the same for both in peacetime, but I doubt that power kero would have been sold 'from the pump' at service stations. Lighting kero was, though. All of them were sold in the old 4 gallon square tins.

Apart from stationary engines, many of the earlier tractors [both wheel and crawler] were commonly made for dual petrol/kero fuel. One advantage these engines had, over the early diesels, was that they could use conventional electric starting.