Hi 78rusty, and a warm welcome to the forum. It's always nice to welcome another Scott Bonnar owner. grin

What a ripper of a machine you have there, and in such nice condition.
Yours is a Scott Bonnar Model 33, first introduced in 1960 and manufactured at Thebarton in South Australia. Inside the chain case you should have a combination of belt and chain drive. wink
Once again 78rusty, :welcome: to OutdoorKing.
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