same problem 4th carb rebuilt. no start when cold until we spray starting fluid then it starts all day.
I heard the unlead gas evaporates due to lower boiling point.any one have this problem with older cars
Had a 59 that was a bugger to start too first thing. If it won’t start after sitting, but will start with starting fluid, I would say that the fuel bowl is emptying. Once you start it, the bowl fills again and its ok. There is a plug under the base of the carb that leaks. Can’t say if it can be epoxied or if the base itself needs to be replaced. Carb kits don’t take care of that problem.
That’s my guess anyway.
How often do you start it? Parts store rebuilt carbs are a joke. Have a local pro rebuild yours and it should operate normally. The gas evaporates, yes, and it can leak out too. A hidden electric fuel pump will solve your problems by filling the carb quickly.
I had a 57, my mother had a 58, great cars. Mine and hers always started on the first hit, mine was one of the quickest starting cars I ever had.
Anyway, these carbs can develop leaks and drain the fuel bowl, as noted earlier. A good fuel pump should put enough gas back in the bowl quick enough to start it, so you may have two problems.
If you have the wrong plugs, it could also be prone to flooding.