The nearest I can get is a Kirby Lauson HK30. This was a 3hp engine. There would originally have been an ID plate attached to the cowl. Production probably started around 1962, and went to about 1967, when the engines became Kirby Tecumseh. I have not found actual production dates, just going by advertising.
If there is a Kirby historian in the audience, I would like to hear from you. My email address is on the left.
Eric