The speed of CF 150-C-C platform changed from 1500 to 70-80. What is the problem when the clutch is tightened and the throttle is released?

When the throttle is suddenly turned off at high speed, the air intake will decrease immediately, which may lead to the mixture being too rich and the engine stalling. If the idle speed is normal, the cause of this situation may be poor transition of carburetor. You can also check whether the mixture is too rich. In addition, you can return to the throttle immediately after closing the throttle. Don't turn off the throttle all at once, it's not easy to turn off the fire.