ADJUST the Scene time Scale AND Stepping Strictness
Add a value of 2 on the Time Scale and 0.5 on the Stepping Strictness. Time Scale works as a factor: a value of 2 means that the fluid will be two times faster. Stepping Strictness calculates how fast the fluid will move within a simulation step. Adjust the speed to stop emitting particles around frame 60. Adjust the speed to 400 on frame 59 and add a keyframe. Change the speed to 0 on frame 60 and add a keyframe.