Mercury - Quicksilver 815956A1 Speedometer Hose Coupling Kit MerCruiser Alpha One Sterndrives 815956A1. Overview. Your speedometer's only as accurate as the connection behind it. The Quicksilver 815956A1 Speedometer Hose Coupling Kit is a simple but essential fix for keeping your speedometer system working like it should. Designed for MerCruiser Alpha One sterndrives (1991-1997), this OEM coupling ensures a tight, leak-free connection between the speedometer hose and the drive unit.. It's a smal