30kg was a conservative over estimate.
That would be a heavy one, Maybe a power torque Victa would get close, they have an all cast irom block making them heavier than a Briggs.
A victa full crank Utility would be lucky to be much over 20kgs.
I do have a couple of SP 21" yardmans here, they weigh a bit.
And i got this back from the seller of the one above
"G'day Bob, The fuel tank is off another model . I had to fit the handle mount that came with that tank. The later model tanks seem to be of a better quality plastic and are less prone to uv damage( i never leave any of my mowers out side except when there in use). Cheers, Glenn."