Re: Gray foam(lots) from exhaust outlet 1957 Evinrude 10hp Home › Forum › Ask A Member › Gray foam(lots) from exhaust outlet 1957 Evinrude 10hp › Re: Gray foam(lots) from exhaust outlet 1957 Evinrude 10hp vintinReplies: 580Topics: 19 June 1, 2018 at 1:03 am #77182 Some of the ‘gray foam’ is from the crankcase drain reed valve system.