Have a 4 stroke 15 hp evinrude ( Model E15R4EEB ser# G04642708 ) that has to be taken off the boat for winter storage. Last winter when taken off it was laid on its side ( don't know which side) and in the spring there was enough oil in the cylinders that the spark plugs had to be taken out to get it to turn over using the pull cord. Some one said they have a 4 stroke (not Evinrude or Johnson ) and there is a decal saying which side to lay it on. This one has no decal. Can this motor be laid down or must it be stored in an upright position?