Bellantonio,

I'm not sure exactly what you are asking here. Sorry, but it makes me wish I spoke Italian. I have a small ability in Spanish, but, we do have a few folks on the forum that are good in your native language, I hope they will drop by.

Are you using the carburator on your engine, or a CL venturii? I would recommend the venturii, but the carburator can be made to work. I'm not sure what you mean by pin on carburator. Are your referring to the needle valve being loose?

Perhaps if you asked your question in Italian?

There should be a small "acorn" type nut that the "pin" (needle valve) inserts into.  This is probably too loose.  Carefully tighten it, (preferably with a small open end wrench but pliers will do if your'e careful) until you get the tension you need.  It is a sensitive adjusment and should probably be set a little on the tight side so it will not rotate with engine vibration.  If that adjusment nut is missing you will have to find another.  Good luck.

There should be a small "acorn" type nut that the "pin" (needle valve) inserts into.  This is probably too loose.  Carefully tighten it, (preferably with a small open end wrench but pliers will do if your'e careful) until you get the tension you need.  It is a sensitive adjusment and should probably be set a little on the tight side so it will not rotate with engine vibration.  If that adjusment nut is missing you will have to find another.  Good luck.

The following is the above text from Pete Cunha, run through an English to Italian translation.  They are readily available on the web.  Valerio...see  if this makes any sense.

Ci dovrebbe essere un piccolo tipo dado "della ghianda" in che "il perno" (valvola ad ago) inserisce. Ciò è probabilmente troppo allentata. Stringala con attenzione, (preferibilmente con una piccola chiave ma le pinze dall'estremità aperta basterà se your'e attento) fino a che non otteniate il tensionamento che abbiate bisogno di. È un adjusment sensibile e dovrebbe probabilmente essere regolato poco sopra il lato stretto in modo da non ruoterà con la vibrazione del motore. Se quel dado di adjusment manca dovrete trovare un altro. Buona fortuna.

Cheers.

Warren Wagner