unusual engine

[vhgmcbuddy]

Well, I thought I had seen them all! But! There is on that well known auction site, a Briggs and Stratton 5 HP engine with TWO output shafts! not front and rear, but both at the back, the seller states it came off a Rotorvator and one shaft turns left and the other turns right! he says the smaller shaft was for reverse. Has anyone else ever seen one of these engines? and I wonder what Rotorvator it came off?

[terrano]

Hi,The drive is an extension of the camshaft which turns in the opposite direction to the crankshaft pulley. When used, a rotavator doesn’t need a reverse gear in the gearbox, I believe some ariens (U.S.A) models used this system. regards Terrano.

[wristpin]

Quite common on US made tillers and have also seen them fitted to snow blowers. Back in the 70s I worked on a Bolens rear engined rider with a vertical shaft Tecumseh that used the same system for reverse while the crank drove the machine forward through a 3-forward speed transmission.
In more recent times Ransomes have used both a Kubota and a Honda with cam drive to get the rpm low enough for their centrifugal clutch on the Mastiff. In that application the rotation of the engine is reversed so that the extended cam is running in same direction (counter clockwise) as a standard engine’s crank to avoid the need to re-engineer the transmission which remained essentially the same as when the Mastiff had first a JAP and then a Swiss made cast iron MAG

[dorigny]

I seem to remember a B&S 3 or 3.5hp coming in for repair, 25yrs ago.! that had a sprocket on the cam drive shaft. I believe the engine was from a small cement mixer.?

Clive.

[stuart]

The 1970,s Landmaster “Lynx” 5hp rotavator used one of these engines.

[Author]

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