Sorry for pause in communication, Max.
So, to summarise, it looks likely that my chassis left the factory in 1961 with a 2-stroke motor, at some stage subsequent had that motor replaced with a 4-stroke (with mounting holes fully drilled out to accept, but centre hole NOT enlarged?) and then, finally, had an earlier model 2-stroke motor plonked on it. It's like researching a family tree!
Outstanding work, Max. Thank you for sharing your knowledge.
Now, the only remaining questions are with regards to what vintage/series/origin the motors are. Does the engine number shown in the original post give any clues? I'm assuming it is a Victa 2-stroke, but.......
Wilbur
