Nice little motor Bob,
i belive that i have 2 of them still about somewhere in the attic. they were originally fitted in model motor torpedo boat built for me by my father when i was about 8yrs old the boat is still about and in reasonable condition. not bad to say im 61 now. Dont know if anyone can remember the batteries it ran on, they were made by ever ready and were about 6ins by 4ins by 3/4 of an inch wide with a row of jack plug like holes on the 6 by 3/4 side which gave various voltages up to i think 6v max. the boat ran as a straight runner at the time, though i converted it to single screw single motor and radio control years ago, the old Mc Greggor Digi Max 2 channel. never ever seen any other batteries like those, anyone shed any light on them. So to speak.
John