Description: Drain Plug for MerCruiser manifold and engine block drain cock. Widely used for draining cooling system for winterization.. To keep your boat running smoothly and efficiently all season long, we provide a wide range of boating accessories. Browse from the wide range of products and choose the right boat accessories depending on your needs, preferences and budget.. Compatibility MerCruiser Manifold & Engine Block Drain Cock; Specifications Weight: 1.27 lbs; .