Hi Connormax

From the black and white image I would think that tank is the same as the Qualcast tank ,I see those tanks on
Villiers engines or JAP engines . https://www.outdoorking-forum.com.au/forum/u...ad/Board/159/main/10027/type/thread.html

Also these tanks are used on reel mowers eg Royal Blade etc.

Or the Go Kart tank could just be made for the Go Kart as you can't see the tank from every angle.

Cheers
Max.