Don't worry, it's a spring one you have to hold down to "turn on" the kill.
Unfortunately it has to face that way because it's on a . VC-160 frame which doesn't allow enough clearance for a right hand snorkel to fit between the frame and the fuel tank. I wanted to use the opportunity to try your carby mod on a charity case like this Franken-mower I found, and I don't have the original left hand snorkel for this configuration, so made do with stuff I had lying about. Yes it sticks out too much but it stays in place and I'll replace it down the track + watch extra carefully where I'm going! This project was mainly to learn.

Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!