What is the function of the primer in a carburetor-equipped engine?

• A. To supply fuel to the inlet port
• B. To start the engine
• C. To prime the oil system
• D. To enrich the mixture at altitude

Answer: (A)

Primers are a starting aid for carburetor-equipped engines. They inject a small amount of fuel directly into the intake air, typically into the intake manifold or each cylinder’s intake port, to create a much richer fuel-air mixture for starting. This richer mixture makes ignition easier when the engine is cold or difficult to start. Once the engine catches and runs, the normal carburetor controls take over. The primer’s job is not to prime the oil system and it isn’t about altitude enrichment.