The reason that geysers stop erupting is because of the water cooling down below the boiling point.
When the water in the geyser cools down below the boiling point the water cannot erupt.
When the water heats up again in the geyser and gets past the boiling point then the geyser erupts again.
It's an amazing sight to see a geyser erupt but just stay a safe distance from them because the hot boiling water from the geyser can be deadly or at lease severely burn you.
So stay far enough back away from the geyser if you go to see a geyser in person.
The way that geysers work is the looping chambers in the geyser trap steam from the hot water.
Then the escaped bubbles from trapped steam heat the water column to the boiling point and when the pressure from the trapped steam builds enough, it blasts, releasing the pressure.