I have a 1994 3cyl 60hp merc outboard motor it only starts if i am engaging the throttle forward all the way while turning the key i have to keep putting the throttle forward multiple times until it actually starts. once i get it started it seems to be running fine until i bring it down to an idle then it dies out. i have changed the fuel filter and also the fuel line i have also sprayed the carbs with carb cleaner but to no avail. the carbs don't look dirty at all. the spark plugs have all been changed, after attempting to start it i looked at the plugs and the top is clean but the bottom 2 are fouled the very bottom plug is alot worse then the 2nd one. i have no idea what it needs any help to this problem would be much appreciated.