Mercury - Tensioner Belt Assembly Verado Series Cast Aluminum 8M0101707. Overview. There's a certain comfort that comes from running a Verado that's been cared for the right way. You can hear it in the steady hum at idle and feel it when the boat lifts onto plane without hesitation. The belt system is a big part of that smooth, dependable feel-and when the tensioner starts aging, the engine lets you know in subtle ways. This Mercury Marine part brings that quiet confidence back. It's built for t