The difference in DI vs IDI isn't all that clear. The old IDI may be somewhat inferior to DI, but even that is generalizing. I have a 2120 with DI, I have tried the new Kubota 4610 with IDI and will hands down take it over the DI 2120 (the 2120 came from the factory with a catalytic converter). Quieter, less vibration, more fuel efficient and no question, less (no) smoke, even under a strain. That doesnt automatically make me feel though that IDI is superior. So much R&D has gone into todays diesels for trucks, which have been primarily DI, ie., the Cummins B5.9L which is now using a Bosch computerized fuel injection pump, all to meet emission standards particularly here in CA. Kubota makes great, no, fantastic DI engines on their larger tractors. Why they went to IDI on the L4610 and smaller units must have had some merit as developing a new engine cannot be cheap. It is the first compact tractor motor to exceed CARB* requirements. The IDI on Kubotas is very good and in my opinion, better then the DI diesels Yanmar and Shibura is building. The old DI on my International 454 is a dirty stinkin diesel with plenty of power, but give me the new Kubota IDI any day. Rat...
*California Air Resoures Board
