A picture might help. Measure cylinder bore and if possible stroke...that will
narrow things down. Are cylinders removable or cast in place liners?
Paint color may/may not be much help as more than a few old mercs were "converted" to newer mercs by use of a can of black spray paint or a brush and a can of any color on hand.
Louis, the color is factory. It is a "green tank" twin cylinder K model 10hp type, but the paint color looks like Wizzie to me. No fuel pump - definitely a tank model. Not split crankcase. Serial number sure is short, eh? But I don't see another digit. E593E on the points cam. Will get pics. JW in Dixie