I also had a Byrd 12/24 hand control. Like you said they would run forever on batteries. My motor shaft bent and leaked. Called them and they sent parts for free and i repaired. Moved to Ark couple years later and Magnet came loose. Called and they had me send motor to plant in Ripley. they replaced entire motor and shipped back to me for free all it cost me was shipping to them. Sold boat to a friend over there in 1990 and he is still running it. Another good motor i had that i really liked was a Silvertroll made in Minnesota. They were foot control with a short handle on the head it had a slip clutch built into the steering head so you could use it either way. I dont know if they sold out or just went out of business but that was also a well engineered and built motor. I have a old Phluger up in the attic that was probably built in early 70's that is a 6/12 that still works but it was tough on batteries.
Proud Member of Team Geezer
Charlie Weaver USN/ENC 1965-1979