Mercury - Console Mount Single Control, With Trim MerCruiser Mechanical Control 8M4507539. Overview. This is one of those controls that doesn't call attention to itself-and that's exactly why people like it. It's a simple console mount for MerCruiser engines with trim, fully mechanical, no electronics hiding behind the dash. The handle has a steady, planted feel when you move it. Not stiff. Not sloppy. The neutral lock is there for the everyday stuff-starting up, idling in tight water, letting s