Hi warwick87, and a warm welcome to the forum. Its great to have another Scott Bonnar owner on board.

Being a 16" machine makes it a lot easier to identify but a photo or 2 from different angles will confirm it.
I believe that your Scotty is a Model 33 (first introduced in 1960) with a Kirby-Tecumseh HK 25, 2.5hp, 4 stroke engine. wink

If it is confirmed that your machine is a Model 33, there is a Parts List in the manuals area for that model which you can download after subscription.
Instructions for doing so are contained HERE

The Model 33 is unusual in that it is driven by both a V belt and chains.... wink
Once again, :welcome:
cheers2

Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member.
Kindest Regards, Darryl grin