Breathing noises from carb???

[JJDebeers]

So I'm down in the engine compartment yesterday checking a new fuel line for any signs of leaking. I hear a strange "breathing" noise coming from my stbd carb. I remove the flame arrestor and put my ear directly to the carb and it's definitely making a faint "hissing" or "breathing" noise. Engine wasn't run for at least 16 hours. I didn't start the engine that day.

Any ideas on what could be causing this noise?

Thanks,
JJ

 

[buick430]

check the pcv line and carb base. otherwise a sucking noise is pretty normal. the engine is under a high vacuum at idle

 

[JJDebeers]

The engine wasnt running. It hadnt run for 16 hours.

 

[greasemonkey]

pressure from fuel vapors pushing on the needlle and seat,check your tank vents for clogs

Or may just be be the "Seashell Effect"!!!