Did you get the information you needed? From the limited information and pics I can only guess at this being a Mk11-C engine, and I will say a Mk11-C based engine. The C denotes the engine size of 147cc. The Mk11-C was an early dedicated industrial engine from Villiers used by a number of machinery manufacturers for quite a long time, into the 1940s, it is common on Allen Scythes with a cooling cowl. I say ‘based on’ because I believe it was the first engine also sold branded as an ‘Atco Villiers’ for Atco machines. The MK11-C design dates to the 1920s and was first launched in 1928, the single-piece barrel and ‘sunburst’ fin pattern on top of the barrel align to that period. Atco had used earlier Villiers engines, e.g. MkVI-C, but they would be Villiers branded engines. Most of the Villiers engine barrels of this time should have the Mk cast into the base of the barrel in Roman Numerals but it may not be put on an Atco Villiers engines if I am correct. I have pictures of them having ‘Atco Villiers’ cast into the alloy crankcase so check for that which would probably confirm my guess. On engine number, the first three digits of yours identify to Villiers their customer for the order, so 636. There doesn’t seem to be any order to these numbers, each customer which ordered engines for machines was given a code to identify them, 636 is probably Atco. I have a list of what I matched up a few years ago somewhere but I have so much stuff and so little time it is all packed in crates. One day…. Therefore, the engine number is actually 2492, made for customer / order 636. The B2577 is a barrel type part number, I have never seen anyone list these out. I am also going to suggest that the engine is just post-war. It is an old design but the use of the customer ID serial number system only started after the war and my notes suggest the Mk11-C engine was on sale until about 1946 so my guess is this kind of date, 45 – 46. If anyone knows the exact date I would like to know as I would update my engine records notes if it goes beyond 1946. Some of the rest of the machine looks more ‘modern’ than earlier pre-war machines. For a small engine size the carb would probably have been the Villiers Lightweight carb. If you want to confirm any of what I think this engine may be get back to me, I get very little time to log on to forums but will check any replies. I was actually trying to renew my membership and my interest was caught by your question! I probably have info on the engine and manuals. Ian
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