I have a 89 bayliner i picked up at the end of last year. i have question on the gas cap. Is the gas cap supposed to be able vent gas. I have gas venting through the cap. I know i need to check the vent line to the tank to see if it is clogged, will do tomorrow. So i need to know if the cap is supposed to be able to vent. Or do i have bad gas cap?