Had a merc rebuild spin a bearing like 20 hours in. The only question the merc rep asked was what oil I had in it. I told him to look under the back seat at the bottles I carry on the boat. Merc oil there . Not one other question , they replaced the long block and picked up all the labor !! Worth it in my mind. Wall mart has the oil packaged as quicksilver just like worst marine. Same merc blend. Mercs oil has had 2 big price increases in the past 2 years , like 15% !!!!!