Hi Scott,
dubious about a couple of things but mainly that hole location. Even when my engine came back from YS I wasn't happy with it so I put the whole lot away and bought a heli. I've dragged it back out again, stripped it put in a new rear bearing and made sure things are "right" but it still just doesn't want to run "properly" mixture wise.

Apart from the hole location, I also think the throttle plate/barrel isn't sealing in the housing properly either. When you disconnect the injector line from the injector and suck or blow on the injector line connected to the throttle body, air just pours in and out compared to the 170. If everything is sealed up tight, the only way in/out of the injector line is via the main needle valve/pump/tank. It shouldn't be flowing or drawing from anywhere in the crankcase (except via the sub needle if it's open)

I'm rebuilding my 170cdi in case I can't get this thing working as I like.

Like this area (start of red arrows) isn't sealing properly allowing fuel to leak in the direction of the arrows into the crankcase instead of following the channel around to the injector line nipple on the body.