Well, seems that the throttle cable sheath as provided by Europa uses a different nut than the fitting supplied by Rotax. The Rotax M6x0.75 nut doesn't work. The Europa 914 installation manual doesn't specify the size or thread of the fittings and nuts used on the ends of the throttle cable sheath. I have a request into Roger for nut or thread specs. Judging from what fits, I'm guessing that the thread is M6x1.0 so I went ahead and ordered a pack of 50 ($5.80) thin stainless steel M6x1.0 nuts from McMaster-Carr.