The US Equivalent should be the L185 with the Z751 engine,
is this the engine you have?
If so parts are available from Kubota, Messicks, Coleman or EBay.
Engine Detail:
Kubota Z751
diesel
2-cylinder
liquid-cooled
45.3 ci [0.7 L]
Bore/Stroke: 2.99x3.23 inches [76 x 82 mm]
Power: 17...