Johnson Pump 81-47238 Marine Sanitation Y-Valve – 1-1/2" ID Ports, 1" Straight

Johnson Pump 81-47238 Marine Sanitation Y-Valve

Part Number: 81-47238 (distributor SKU: 189-814723801)
Brand: Johnson Pump
Type: Marine sanitation Y-valve
Port size: 1-1/2" inner diameter (barb ports)
Straight connection: 1" straight adapter
Weight: 1,814 g (4 lb)

Product Overview

Heavy-duty marine sanitation Y-valve for use in marine toilet (head) plumbing systems. A Y-valve is the key fitting that allows a marine toilet to be switched between two discharge paths — typically a holding tank for in-port or restricted waters use, and an overboard discharge for use in open water where permitted. The 81-47238 features 1-1/2" inner diameter ports and a 1" straight connection to suit compatible hose and adapter configurations.

• 1-1/2" inner diameter ports for standard marine sanitation hose
• 1" straight connection / adapter port
• Robust construction for long-term marine sanitation service
• Weight: 1,814 g (4 lb)

Compatible Applications

• Marine toilet (head) systems using 1-1/2" sanitation hose at the main ports
• Installations requiring a switchable discharge path between holding tank and overboard
• New sanitation plumbing builds and Y-valve replacement projects

Fitment Note: Confirm hose inner diameter at all connection points before ordering. Measure existing hose ID and verify the 1" straight connection matches the adapter or fitting at that port on your installation. Y-valves are not universal — port size and configuration must match the existing plumbing layout.

Part Number Reference

• Johnson Pump: 81-47238
• Distributor SKU: 189-814723801

Important Regulatory Note

In US waters, marine sanitation devices (MSDs) and overboard discharge are regulated by the US Coast Guard and may also be subject to state and local no-discharge zone (NDZ) rules. A Y-valve connected to an overboard discharge must be secured (locked or wire-tied) in the holding tank position in any designated no-discharge zone. Consult applicable regulations for your cruising area before configuring your sanitation system.

When to Replace

• Valve handle is broken, seized, or no longer rotates to both positions
• Internal seals are leaking and cannot be restored by a gasket/seal kit
• Valve body is cracked or physically damaged
• During a full sanitation system overhaul or hose replacement

Installation Notes

• Confirm all hose inner diameters match the valve ports before final installation
• Use marine-grade sanitation hose clamps at all connections — double-clamp below the waterline
• Install the valve in an accessible location so the handle can be operated and the valve can be serviced
• Label the valve positions clearly (holding tank / overboard) to avoid accidental mis-direction
• Test all connections for leaks before putting the system back into service

Technical FAQ

What is a Y-valve used for? A Y-valve lets you switch your marine toilet discharge between two paths — usually a holding tank (required in restricted or no-discharge zones) and an overboard through-hull (permitted only in open water in areas without NDZ restrictions).

Do I need to lock my Y-valve? In US no-discharge zones, yes. The Y-valve must be secured in the holding tank position. Many boaters use a zip tie or padlock through the handle to comply with USCG requirements.

Related Products

• Y-Valve Gasket Kit
• 1-1/2" Y-Valve
• Forespar 902000 Marelon Y-Valve – 1-1/2" Barbs
• Forespar 902001 Marelon Y-Valve – 1" Barbs
• Forespar 902017 Marelon Y-Valve – 3/4" Barbs
• Forespar 902018 Marelon Y-Valve – 1-1/8" Barbs

Parts Desk Insights

The most important pre-sale check for 81-47238 is confirming the hose inner diameter at all three ports — the two 1-1/2" barb ports and the 1" straight connection. Customers frequently measure hose outer diameter instead of inner diameter and end up with a misfit. Also confirm the installation has enough space to access the valve handle for switching, and remind customers of the no-discharge zone locking requirement. If the customer only needs to rebuild an existing Johnson Pump Y-valve rather than replace the whole body, point them to the Y-Valve Gasket Kit first.