Jet erupts every 1 to 4 minutes during most Fountain Geyser eruptions. After Fountain has quit, Jet usually quits. Approximately mid-way through a Fountain Geyser interval, Jet often starts a new eruption series.
The Fountain Geyser erupts every 1 to 4 minutes, and Jet typically follows suit after Fountain has stopped erupting.  Jet frequently begins a new eruption sequence about midway through the time between Fountain's eruptions.