Which statement best describes the choke and engine warm-up?

Which statement best describes the choke and engine warm-up?

• A. The choke should be left ON after warming up.
• B. The choke is not necessary on any motorcycle.
• C. The choke is used to enrich the fuel and should be turned OFF when warmed.
• D. The choke increases fuel consumption.

Answer: (C)

The choke’s job is to enrich the fuel-air mix to help a cold engine start and run smoothly until it reaches operating temperature. When the engine is warm, you should turn the choke OFF so the mixture returns to normal. Leaving it on after warming up makes the mixture too rich, which can cause rough idle, black exhaust, fouled plugs, and wasted fuel. Some bikes today use electronic cold-start enrichment or no choke at all, but for carbureted engines the practice is to disable the choke once warm. This is why the statement about the choke enriching the fuel and being turned off when warmed is the best description.

The choke’s job is to enrich the fuel-air mix to help a cold engine start and run smoothly until it reaches operating temperature. When the engine is warm, you should turn the choke OFF so the mixture returns to normal. Leaving it on after warming up makes the mixture too rich, which can cause rough idle, black exhaust, fouled plugs, and wasted fuel. Some bikes today use electronic cold-start enrichment or no choke at all, but for carbureted engines the practice is to disable the choke once warm. This is why the statement about the choke enriching the fuel and being turned off when warmed is the best description.