This picture was contributed by George S. Clark, 254 Pond Point Avenue, Milford, CT 06460. It is a 6 HP United States inverted upright. Bore is 6' and stroke is also 6'. Serial Number is 10657.
'It is a little unusual since it has a heat exchanger for both the fuel and the air intake. I suppose this is for using kerosene or gasoline. It also has only one port that functions as both intake and exhaust port with an odd arrangement for closing off the intake when the engine exhausts. It's a real strong running engine.'
This Rock Island 'Heider' tractor belongs to William P. Riekena, R.F.D., Wellsburg, Iowa 50680. It was purchased by his father in 1924, as a seven-year old used tractor. It was used mostly for belt work shelling and grinding feed. The tractor was made in 1917 and is a Model C, rated 12-20 HP. It has a Waukesha engine bore 4', stroke 6'.