I recently lost the sump oil drain plug from my 2008 Yamaha 4hp 4 Stroke. When I ordered the replacement part/s, I was sent a hex-headed drain screw and two slightly differently sized metal [steel?] washers.The Yamaha manual refers to there being a gasket and when I queried this with the suppliers they checked and advised that the metal washers are the gasket. Does anyone happen to know if this is correct and if so which way round the two are supposed to be used?