I always wondered if 16/2 self starting units existed. Is this a SOM then?
It should be, but I cannot see the startomatic components that you would expect to see on the engine, these will be on the side closest to the alternator. Lets hope so for your sake they are present, because these parts are unique to the twin cylinder startomatic sets.
I was ready to bid big money for it and couldn't believe when the hammer dropped for £450 !!!
Luck was on your side that day
I'll get more photos in the next few days.
Can't wait.
Having looked at the photos in more detail this engine would have been radiator cooled. The style of water manifolds, and two unused studs (for water pump) on the crankcase and behind the flywheel. Are all indicative features of a radiator cooled engine.
If you PM your email address, I have stored away somewhere some photos of a twin cylinder startomatic set that would show this detail, and hence give you an idea of any parts you be missing. But please be patient as this will take me some time to find.