These Kubota engines are a refined version of the Chinese horizontal water cooled singles. they have a good reputaion for quality factor. The Kub is an aluminum block engine and the China diesel is all cast iron. For a portable application aluminum makes the most sense, but cast iron is a clear winner for an engine block in the` made to last a long service life` camp. It is this cast iron block, and yes, nice machining of the China diesels that makes me prefer to spend my money on one of those instead of a Kub engine of equal horsepressure, given a choice. In addition to the cast iron the China diesel is spec`d for rated power at lower RPMs. You can get almost full power from a 2200 RPM Changfa or clone 1115 engine directly driving an alternator head at 1800 RPM. The same Kub engine will need to spin 3200-3600 RPM to make it`s faceplate rated power. Slower means not only much reduced wear, but also higher fuel efficiency as more time is available per bang cycle to squeeze a good complete burn from the slow buring diesel or heavy fuel oil.
The new China diesel can be had for the same price as a good condition used Kubota of similar power. The Kub parts are much more expensive. The Kub will not last nearly as long. For a stationary power plant the decision of which to purchase is a no brainer for me. I see a Changfa 1115 in my future likely to serve as direct back-up to my currently much relied upon DIY 1.5 litre, 9 kW 3-ph, VW Rabbit diesel powered generating plant in the shop.