A heat exchange system for use on an engine-powered watercraft includes a liquid cooling system for cooling the engine using a first heat exchanger and a water heating system using a second heat exchanger for heating water. Raw water from an external water source is passed through each heat exchanger. Water used to cool the engine coolant inside the first heat exchanger exits the watercraft. Water heated by the second heat exchanger is passed to either an intake conduit or at least one onboard accessory system for flushing thereof to kill aquatic invasive species. A valve inside the second heat exchanger opens to release heated water when the heated water reaches a temperature of at least 140 F. Heated coolant from the first heat exchanger passes through the second heat exchanger to transfer heat to the water inside the second heat exchanger.

A cooling system for a marine engine has a cooling jacket disposed in thermal communication with a heat-emitting portion of the marine engine. The cooling jacket has a water inlet, and a water outlet on an upper portion of the cooling jacket. A pump is connected in fluid communication with the water inlet and/or the water outlet that causes water to flow through the cooling jacket in order to cool the heat-emitting portion, wherein a flow velocity of water in the cooling jacket is low such that debris sinks to a lower portion of the cooling jacket. A debris outlet is in the lower portion of the cooling jacket that expels the debris from the cooling jacket.

A V-type engine in which exhaust pipe arrangement is easily performed and purification of exhaust gas can be performed by a single catalyst. Cylinders where pistons operate are arranged in a V-shape, a crankshaft driven by the driving of the pistons is disposed vertically, exhaust pipes communicating with exhaust openings in the respective banks of a cylinder head are included, rear exhaust pipes in the respective banks are merged outside on a side of the crankshaft, and a catalyst holder that holds a catalyst is provided in a merge portion of the rear exhaust pipes. Since the rear exhaust pipes in the respective banks are merged and the catalyst holder is provided in this merge portion, exhaust gas from each bank can be purified by the single catalyst, so that the number of catalysts installed is reduced to thus be able to reduce manufacturing cost.

The Outboard motor quick connect system allows the user to easily flush an outboard boat motor by combining a permanently-affixed quick-connect fitting with a locking and sealing cap. The combination allows the quick-connect fitting to remain affixed to the motor, but without creating a risk of leaking during operation. The prevention of leaks is important because the flushing connection is part of the boat cooling system. When the boat motor is in operation, an internal pump draws surrounding water up into the motor. If the flushing connection is left open, or leaks, the water drawn in by the pump will be lost, exiting through the flush connection. Thus, while having an easy to access flush connection is important to encourage the user to flush the engine, it is critical that the connection is watertight.

An antifreeze delivery system includes a container that defines a chamber for containing a volume of an antifreeze. The system further includes a conduit having an upstream end and a downstream end. The upstream end of the conduit is fluidly connected to the container to receive the volume of the antifreeze from the container. The system further includes a cap assembly that fluidly connects the downstream end of the conduit to an inlet opening defined by a top rim of a sea strainer. The cap assembly includes a lid having a planar wall with top and bottom surfaces. The lid defines a channel extending between the top and bottom surfaces and receiving the downstream end of the conduit. The system further includes one or more fasteners for attaching the lid to the sea strainer and sandwiching a seal between the lid and the top rim of the sea strainer.