I did not see any pictures of the starter area. I have those parts . They were hard to find until I new what I was looking for. The only year that starter was used was in 1959. It was the only year that starter was used on the Suburban. The manual does not show the correct parts that you need. It shows a spring. instead of two pulley's.
So if yours is a 1961 Your tractor was more than likly a pull start tractor with a electric start kit available for pull start tractors. That style starter will not turn the motor without having the release lever for the belt. I know first hand. I cannot tell by your pics if it is there.
I can ask my son to CNC the parts you need but you first have to find a starter. That motor with that starter was used on other equipment. Just a different style pully set up.
On the last two pics of the variable pully you can see the difference in the two Pull start verse electric. The page shows you the operation. 1959 only and the tractors were red under the gold which made them look copper compaired to others. The pull starts were green under the gold. This is 59 I am not sure of other years . But yours looks green.