The emulsifier tube that comes in our kit is a slightly smaller diameter and doesn't fit snug in the carb like the old ones do (especially without the all the corrosion and buildup on the old ones). Nevertheless, we haven't had any actually problems with their function considering the jet retaining clips hold the jets and emulsifier tubes in once the float bowls are installed. If they do give you problems, try the original emulsifier tubes and see if the problem doesn't go away. As long as the passages are clear there's nothing wrong with running and old emulsifier tube. If you're missing your jet clip(s), we have some replacements: