Photo attached.
I've had this engine apart and rebuilt it and I don't remember a gap in the output shaft to suggest that this is a collar. I'll have a closer look today.
As to the colours, I know that they are not correct, but I've never liked painted engines and the mower looks good as it is. Each to his own, I guess. Lucky there are no concours events for mowers

Chris
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2012/06/full-5834-6714-engine_cowling_numbers.jpg)
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2012/06/full-5834-6715-output_shaft.jpg)