The best way to fix a Zama carb is to exchange it for a Walbro.

There is very little tech info available for Zama carbs, the kits for them are usually around 3 times or more the price of one for a Walbro, and I have found the diaphrams to be more sensitive to alcohol.

They work fine when set up properly though.

Just my two cents....
AV8TOR