I had the same problem. The plastic bushing was bottoming out so I could not fully tighten the carb to the manifold. Take out the bushing and use a little sand paper to slightly widen the gap in the bushing. Solved the problem for me.How do I keep my CNS carb from vibrating off the engine? I have a great setup and am getting great speed, but the engine hits the high revs and off she goes. I've tried using fuel hose because the rubber o-ring appears to have disintegrated.
If Jim sees this: could you please develop an intake exactly for the CNS?