I have an 85 HP Merc that was given to me before it made someones trash. It a 4 cyl and it still runs although it needs some work. As I'm not yet to familiar with outboards, I was wondering if someone could tell me what the tube (rubber hose line) that is between the 2nd and 3rd spark plug and what is its purpose. This line on my engine looks totally blocked.<br /><br />Thanks for any help