The Air Starter, Cold Start Mechanism and Water Cooled Exaust manifold would suggest it is not automotive, but for a marine application.
Known to have been one of a large batch of engines refurbished in the late 1970’s (see date 1978 on exhaust manifold flange) most of which were exported.This one “missed the boat”, was neglected, and eventually left outside exposed to the elements for 30+ years.
The colour, duck egg blue/green was typically used on military engine and gearbox which had been rebuilt by the REME.
The Starter and most of the fuel system was seized and required lots of TLC to get it operational.
Restored July 2017.
Recovered from a breakers yard, Mirfield, June 2016.