Perko Flush Pro Engine Flush Valve, For Inboard Engines, Polymer, Stainless Steel Spring, Transparent Body

Overview

The Perko Flush Pro is a marine engine flushing valve range for inboard raw-water cooling systems, with configurations for 5/8 inch, 1 inch, and 1-1/4 inch hose sizes. It lets a boat owner flush the engine with fresh water through a standard garden hose connection, including while the boat is in the water, so routine salt removal does not require hauling the vessel or breaking into the cooling line.

The valve works by drawing fresh water into the engine cooling system once the cap is removed, the hose is connected, the water is turned on, and the engine is started. A check valve system activated by hose water pressure shuts off the hull intake during flushing, helping direct fresh water through the system instead of pulling seawater through the seacock.

Flush Pro also supports winterizing through a 5/8 inch winterizing fitting used with tubing and antifreeze after the seacock is closed and the system is drained. The clear polymer body lets the operator see water flow, and the internal spring is stainless steel for use in a wet engine-room environment.

Key features

• Freshwater flushing valve for inboard engines with raw-water cooling systems.
• Available for 5/8 inch, 1 inch, and 1-1/4 inch hose installations.
• Check valve system is activated by water pressure from a garden hose and shuts off the hull intake during flushing.
• Clear polymer body allows visual inspection of water flow during use.
• Stainless steel spring inside the valve for service in damp marine spaces.
• Can be used for engine flushing and winterizing when installed in the correct section of the cooling system.
• Suitable for onboard generators when the hose size and raw-water plumbing layout match the selected configuration.
• Made in the USA.

Variants

This Flush Pro range varies by included package and hose size. The available configurations include valve-only versions, valve and kit versions, and a European valve and kit version for 1-1/4 inch hose, also listed as 31.75 mm.

Across the range, the main buying decision is the raw-water hose inside diameter on the engine or generator installation. The valve and kit versions add the kit package to the valve, while the valve-only versions are suited to installations where the matching accessory pieces are not needed or are already on board.

Installation and setup

Flush Pro is installed in the raw-water cooling circuit, so hose size and placement matter. Before ordering, the hose inside diameter should be matched to the existing engine or generator plumbing, and the installation should leave enough access to remove the cap, connect a garden hose, and visually confirm water flow through the clear body.

For use, the cap is removed, a standard garden hose is connected, water is turned on, and the engine is started. After flushing, the engine is shut down, the hose is disconnected, and the cap is replaced. For winterizing, the seacock is closed after draining, the winterizing fitting is inserted, and antifreeze is drawn through the engine using 5/8 inch tubing.

Use cases on board

This valve is a practical fit for inboard-powered boats that need regular freshwater flushing after saltwater use, especially vessels kept in the water between trips. It is also useful for owners who handle their own seasonal layup and want a cleaner way to introduce antifreeze through the raw-water side of the cooling system.

It is most relevant in engine rooms and generator spaces where the raw-water hose run is accessible and where visual flow confirmation is useful during maintenance. The clear body is especially helpful when one person is managing the flush from inside the boat and wants quick confirmation that water is moving through the system.