Are you sure it's a V1902 and not a V1901?
The exact number and serial number can be found stamped on the block just on the flat next to the injection pump facing up.
The reason I ask is I don't think the V1902's came out till they switched model #'s to 4 digits, But there are a ton of oddities in kubota and especially with Grey's.
There is actually 2 V1902's out there.
I would need to know if it is a IDI (indirect injection) or DI (direct injection) engine.
The IDI engine will have fat short injectors, and the DI will have long skinny injectors.
V1902 IDI
V1902 DI
Also, does it have a spin on filter or a cartridge filter, and where is it attached?