The starting of a supersonic air-intake at the design Mach number depends on the internal blockage due to flame-holder struts in the combustor. In the present work, the starting of a two-dimensional supersonic air-intake for scramjet operation was verified experimentally on an isolated full-scale truncated model. The first ramp of the supersonic air-intake was truncated and simulated from downstream of the second ramp where the local Mach number was 3.7. The flight mission dictated the opening time of the cowl plate to be fixed as 200 mS. The maximum blockage of struts which allows the intake to start was determined by varying the blockage ratio in the range of 20% to 30%. The results indicate that the intake starts when the blockage ratio was 20%, but unstarts for 25% and 30%. In the unstart condition, discrete frequencies of 45 Hz and 60 Hz occurred and pressure fluctuations in the intake showed limit cycle oscillations. A detailed analysis of unsteady pressure fluctuations confirms that the buzz could be modeled as a Van Der Pol oscillator with nonlinear damping.