Several Ebay vendors sell Loncin engines ( some branded differently ) which will drop strait in
One of the junk tool shops , Gasweld / Total Tools / Sydney Tool Box sells Preditors ( which are also Loncins ) and another one imports Ducars but I think only horizontal shaft models, can't be sure as I almost never shop at any of them , or Bunnings ( where lowest prices are just the beginning,,,, of your problems ) .
There is no HF down here because our retail laws have a manditory 12 month warranty , unlike the USA where most of them expire the second you walk out of the door .
Thus flogging off absolute trash is not an available business plan.
The same laws have protected us from the perils of Walmart as well
And probably went a long way towards the failure of the Lowes / Woolworths Masters chain although the total inepitude of 99% of Australian managers & all directors would not have helped . I think one of those rejects is now destroying the biggest local after market parts suppliers, RGS .
What is wrong with the Honda ?
Rover only ever made lawn mowers & shredders in OZ everything else was rebadged from OS
These were painted blue hammertone
Some time in the 70's they moved from Sydney to Brisbane and stopped making ride ons & changed to red .
Then around 2000 they were taken over by MTD so if it helps other to help you it is either a rebadged MTD or a fully imported Chinese machine .
Measure the shaft diameter on the engine it should be 7/8" if it is a push mower engine or 1" if it is an industrial engine .
A fully imported Chinese one can even be 25mm if it is an EU model.
Just about any 4 stroke engine with the same shaft diameter will fit , but be careful because USA mowers all have some sort of blade brakes so the output shafts are usually longer than Australian mowers as we learned not to run over our own feet back in 69 when Victa stopped making their Toe Cutter model .
FWIW B & S and Honda have the same bolt pattern for push mower engines so if you want to pinch one from a rusted out mower you will be spoiled for choice .
Victa 2 stroke engines will not fit .