The way to gauge it is not with the engine running but with the engine off. The plate should be at the bottom of the portion of the airflow cone that has verticle sides. There is a small length of the cone that is machined flat. As the plate leaves this area the gap grows quickly. It should be in the area of continuos gap, but just about to leave it. Once the motor is running the plate drops into the area of significant gap and the amount depends on engine speed and mixture adjustment.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician