1976y Merc 500 Carb connection linkage

[rwgiles]

I am renovating a 1976 Merc 500 - 4 cylinder 2 carb engine s/n4361736. The plastic link rod between the lower and the upper carb is broken. I can't find it on your site. It is plastic with 2 holes molded into it to allow flexibility. It is about 4" long and screws to the throttle shaft of the lower carb and inserts into a slot in the upper carb throttle shaft.
Where can I get one of these?