G'day QSR,
Going by the Gregorys Small Engines #199 service/repair manual, Kirby used two brands of carbies on the HK25's, and you may have one of each. The brands were Tecumseh and Walbro, and they used several different models from each of these makes.
The one in your 2nd pic is a Tecumseh for sure; that in the first pic may be a Walbro. Edit: Walbro carbies will likely be a lot easier to find parts for, as Walbro is still in business, unlike Tecumseh.
You'll need to find the maker's part number on the throttle body to tell for sure; if it's a Walbro the part number will have a LMG or GEW prefix.
The Tecumseh carb models Kirby used all had a 270L part number prefix.
So I decided to clean one of the carbs today. Got the motor going but it's in desperate need of a freshen up, oil leaks central. I think I'll stick with this carby as it looks cleaner without the primer bulb which will be hard to find. This model of the hk25 has the breather tube going into the air filter elbow where the other had the hose at the bottom of the mower and would leak oil everywhere. So I'm guessing this is a newer improved version.
The ultrasonic cleaner did most of the work, some before and after shots, would this be the tecumseh carb?