In answer to query 40/5/2 (GEM, May 2005, page 6), the unknown engine in question is a Lockwood-Ash marine engine. It is probably a Model B, built in the 1925 to 1930 era. The homemade wooden pulley mounted on the PTO says that someone modified it for stationary engine work rather than marine use. This engine does not follow the norm of the day produced by Lockwood-Ash, since those engines were typically single- and multi-cylinders of a 2-stroke design, water-cooled and vertical cylinder(s), rather than opposed and horizontal. Little, if anything else about these engines is known as far as I have found.
Seeking information is a tougher job sometimes than the actual resurrection of the engines themselves!