A four cylinder water-cooled side valve engine, built to Edgar Westbury's "Seal" design, intended for larger model boats. It turns over freely, has compression and the valves all move. The distributor and plug leads are currently disconnected and it appears to be set up for glow plug ignition at the moment.
Hemingway still stock castings, drawings and the design manual for this engine, there is more information about it on their website here.
Length 8 inches
Flywheel 2 1/2 inch diameter
Base 12 x 4 1/2 inches