The horizontal bent beam 100 engine was replaced by a carburetor with larger caliber. After the emergency throttle, the idle speed increased for a period of time, and then returned to normal. Why?

The main problem is the carburetor. The engine can increase power or speed without increasing the carburetor, and the power output carburetor of the engine will be updated as long as it is adjusted to the limit.

When you change a carburetor with a large caliber, the air flow rate is the same at the same speed, but because the carburetor has a large caliber, the throttle opening becomes smaller, the air velocity at the throat becomes smaller, and the negative pressure becomes smaller, which will reduce the gasoline injection, that is, the mixed steam becomes thinner. Idle speed after slamming on the throttle is a kind of air leakage phenomenon, and others are also a manifestation of large carburetor diameter, correspondingly reduced throttle opening and reduced negative pressure.