The counterweight, plus the volume of exhaust gas at any speed above idle, will force the heat riser to the "cold" position as soon as the engine starts if the bimetal spring is disabled. It really is necessary for a quick warmup even in so-called "warm" climates. It should be completely released due to the geometry of the flap and pivot shaft within 5 minutes or less after startup.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!