I have a 1996 120 HP Force OB. When I pull boat from water & set on trailer, a very small amount of coffee colored oil/water mix will leak from the water intake vents on lower unit. Could this be caused by oil/gas residue when motor is turn off & tilted up? Do not see anywhere else. Not enough to run down lower unit. I probably should check the LU oil but the leakage is very small & smells of gas. -- Thanks