On the next model of the F engine, the carbureted 3F that was available in other countries, there is no mention anywhere in the Toyota 3F engine manual of using the Lean Drop method to tune the carburetor at idle.
The carburetor on the 3F engine has an idle mixture screw like our 2F, but Toyota no longer felt that using the lean drop method to tune it was adequate (because it’s not very precise).
The way they recommended that the 3F idle mixture be set is to use an exhaust analyzer to actually measure the air fuel mixture blowing out the tail pipe. .. And these 3F engines didn’t have smog equipment either.
That being said - there isn’t an exact way to set the idle mixture perfectly on a 2F engine by using the lean drop method. The best you can do is follow the instructions given in the Toyota manual and cross your fingers. - or get an exhaust analyzer.
The idle mixture screw on the USA carburetor was capped with a security plug to prevent tampering for the life of the carb. It’s not like the idle mixture ever needs to be fiddled with once it’s set correctly.
The carburetor on the 3F engine has an idle mixture screw like our 2F, but Toyota no longer felt that using the lean drop method to tune it was adequate (because it’s not very precise).
The way they recommended that the 3F idle mixture be set is to use an exhaust analyzer to actually measure the air fuel mixture blowing out the tail pipe. .. And these 3F engines didn’t have smog equipment either.
That being said - there isn’t an exact way to set the idle mixture perfectly on a 2F engine by using the lean drop method. The best you can do is follow the instructions given in the Toyota manual and cross your fingers. - or get an exhaust analyzer.
The idle mixture screw on the USA carburetor was capped with a security plug to prevent tampering for the life of the carb. It’s not like the idle mixture ever needs to be fiddled with once it’s set correctly.