hello All

I urgently need to know why carb' float levels are so imporant and how these are set on the 4A Solex. Are there any tools or gauges that are required? Regrettably I have no servicing manual and technicians seem underinformed on these units. I'm told that precise setting of the 'second stage flap' is important??
This car struggles to get engine revs from pulloff and burns rich except for long hard runs when exhaust colour is perfect light grey.

Any help will be greatly appreciated

Ed Cumings