This is an older problem I ran into, but one I remember fondly.  Sort of.

For some reason, my propane BBQ refused to get hot.  The flame would light, but stay so low, the BBQ would never provide enough heat to melt a chocolate bar. 

What I didn’t realize is that newer propane tanks contain a self regulating feature that will automatically slow down the flow of fuel if it thinks it’s too high.  Nice feature – but one that I missed in the documentation. 

To get fuel back to full flow, just disconnect and reconnect the tank from the BBQ.  This will reset the regulator, and you should be able to light’er up and grill away.

Happy grilling!