The fast idle cam and spring are located inside the choke housing, assuming you have a 967s with automatic choke. 966s is manual choke.

If the fast idle cam and spring on a 967s are correctly installed, the fast idle spring is good, and the fast idle link adjusted to specification, then the engine should fast idle.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop