Interesting configuration. As for priming, can you see where the output side of the priming pump goes? One type of start assist sprays fuel into the intake manifold and ignites it. Perhaps that's what this tractor has. It could also be to prime the main diesel injection system but usually that priming only happens once after air is introduced into the system (e.g. after a filter change) and not on an everyday first start scenario. I'm also curious as to why that control is on the other side of the engine - perhaps it's a remote governor control since the rod seems to go down towards the governor. In any case, that's a nice looking unit that would be great to see in operation, especially if that awesome "paint job" is left alone

The pictures from the show are of a U-series D2, which has a different engine to the 3J machine that you first posted about.