I changed the hydro oil in the Encore Premier Walkbehind last night and found that 9 quarts (as specified in the manual) is to much!
I drained the hydro tank and changed the filter, after about 8-1/2 quarts it started overflowing.. So I figure there was still some old hydro fluid in the lines/pumps.
I decided to go with a cheaper brand oil, SuperTech 20w-50 Synthetic.. Walmart brand!