OMC Evinrude Johnson Seal Throttle Body

The OMC Evinrude and Johnson throttle bodies typically feature a sealed, rotating shaft with a throttle plate that controls airflow into the engine's intake manifold. This design helps maintain a tight seal to prevent air leaks, which could affect engine performance. The throttle body is connected to the throttle linkage, which is activated by the operator's throttle control. 

Here's a more detailed breakdown

Throttle plate.

The throttle plate, also known as the butterfly valve, is a rotating plate that controls airflow in the engine.

Throttle Shaft

The Throttle shaft is connected to the throttle plate and rotates with the throttle plate

Sealing

The throttle body is designed with seals or gaskets to ensure a tight fit and prevent air leaks around the throttle plate and shaft

Location:

The Throttle body is located between the air cleaner and the intake mainfold

Function

The throttle body's primary function is to control the amount of air that enters the engine, which directly impacts the engine's power and speed.