I've pulled and cleaned the sensor. My question is about the metal washer that sits behind the oring. I can't tell if the washer has deteriorated or if it was buildup that I removed. It almost looks to be like metal flakes I was cleaning off of it. The washer is much thinner than before the cleaning. The washed is still in good round shape just much thinner. I would hate to reinstall everything and something go wrong bc of this washer. I also hate to waste time and money if it's normal. If there is anyone the can shed some light on the subject it's much appreciated. Thanks

http://www.bbcboards.net/yamaha-motors/33301-ox66-o2-sensor-removal.html It is highly recommended to order the new "O"ring and gasket before removing the O2 sensor.

That's the thread I went by to clean mine. I order the kit assuming it came with the washer and oring but it didn't. It only comes with the housing gasket. I know the metal ring has a purpose, just not sure what it is as the oring seals it. I'm going to swing by Rockwall marine tomorrow and let them take a look at it. Thanks