D-I-Y Boat Winterizer Engine Flushing SystemQuickly and efficiently service inboard/outboard marine engines. The Do-It-Yourself Winterizer allows flushing and preparation of boat engine for winter storage with just five gallons of antifreeze and your flusher. Save time and money season after season. Great for technicians, too. For front mounted raw water pump systems, use the Flush Adapter, sold separately.