That looks like the carb for the Enya .11 engine?
The Enya .09 carbs have a neck diameter of 7mm, if I remember correctly, and they are a direct drop-in on the PAW .09 engines.
It sounds like the barrel is too lose on the PAW 55, a common problem with the early carb bodies that where made out of aluminium. In the past I have simply remade the carb barrel from Teflon instead, these can have a tighter fit and still slide nicely in carb housing. Here is an example on the PAW .09 engine;
