Ok, this maybe a really stupid question, but how do you listen to the radio with the boat engine not running? When I turn the key "on" I can turn the radio on but it also triggers the warning beep which as far as I can tell just keeps going till the boat is started or you turn the key back off. I looked through the manual and searched online and couldn't find anything about this. Maybe it's not possible but that doesn't seem right. Any help is appreciated, thanks!