I have an update on mine. It is a komet motor, and is now on the survivor list
You have a Hartman (as you're aware), It's a 1977 Blue Streak with a Komet K55 reed engine. It's a very desirable kart for vintage enthusiasts and yours is period correct, it appears to have been repainted but could have possibly been painted green by request of the original purchaser. I'm adding you and your Hartman to the survivor list today.
Rod
Rod Van Deusen