Jabsco Twist ‘n’ Lock Manual Marine Toilet Pump Assembly

The Jabsco 29040-3000 Twist 'N' Lock Pump Assembly is a complete replacement pump for compatible Jabsco manual marine toilets. Its double-acting piston pump manages bowl rinsing and waste discharge, while the 90° Twist 'N' Lock handle closes the waste outlet valve after use to help guard against siphonic flooding and waste backflow. The assembly is supplied with its discharge elbow, joker valve, base valve gasket and a spare discharge-elbow screw.

Jabsco Twist 'N' Lock Replacement Pump Assembly

The Jabsco 29040-3000 replaces a damaged, worn or older-style manual toilet pump assembly without requiring replacement of the complete toilet.

It is suitable for both compact and regular-bowl Jabsco manual toilets within the compatible 29090 and 29120 ranges. The pump can also upgrade compatible earlier grey- or black-handle manual toilet pumps to the Twist 'N' Lock operating system.

What Is the Jabsco 29040-3000 Used For?

The 29040-3000 performs the toilet's manual flushing and waste-pumping functions. During operation, its double-acting piston pump draws waste from the bowl, introduces flushing water and then discharges the waste into the sanitation hose.

The wet-bowl and dry-bowl control allows the toilet to rinse with water or pump air through the bowl to leave it substantially empty after use.

Which Jabsco Toilets Is It Compatible With?

• Jabsco 29090 Series compact manual marine toilets
• Jabsco 29120 Series regular manual marine toilets
• Jabsco 29090-5000 compact Twist 'N' Lock toilet
• Jabsco 29120-5000 regular Twist 'N' Lock toilet
• Jabsco 29120-5100 regular Twist 'N' Lock toilet
• Current Jabsco Twist 'N' Lock manual toilets
• Compatible earlier grey-handle Jabsco manual toilets
• Compatible earlier black-handle Jabsco manual toilets
• Compact and regular-bowl configurations using the rectangular four-screw pump mounting

The pump does not fit the obsolete Jabsco 59128 Series, which uses a triangular three-screw pump mounting rather than the later rectangular four-screw pattern.

How Does the Twist 'N' Lock Mechanism Work?

After pumping the bowl clear, push the handle to the bottom of its stroke and rotate it through 90°. The remodelled piston is then held down against the base outlet valve, keeping the waste outlet securely closed.

Turning the handle back to its normal operating position releases the piston so the pump can be used again.

This locking action helps prevent waste from flowing back into the bowl and provides additional protection against siphonic flooding. It supplements a correctly installed sanitation system and does not replace seacocks, vented loops or other required anti-siphon protection.

How Does the Manual Pump Operate?

The Jabsco pump uses a double-acting piston design:

• On the upward stroke, waste is drawn from the bowl into the lower pump chamber while flushing water is delivered to the bowl
• On the downward stroke, waste is discharged into the outlet hose while flushing water is drawn into the upper pump chamber
• In dry-bowl mode, the pump uses air rather than rinse water to help clear the bowl
• The flush-control lever operates the automatic vacuum breaker
• Spring-assisted top-valve closure helps the pump prime
• The constant 38mm waste path helps minimise blockages
• The full-bore aortic joker valve provides automatic backflow control

The associated manual toilet pump can self-prime from dry with the flushing-water source up to 1m below the toilet base and discharge waste up to 3m above the base.

Key Features

• Genuine Jabsco replacement pump assembly
• Jabsco part number 29040-3000
• Complete pump assembly for compatible Jabsco manual toilets
• Twist 'N' Lock 90° safety handle
• Remodelled piston locks against the base outlet valve
• Helps prevent waste backflow into the bowl
• Provides additional protection against siphonic flooding
• Powerful double-acting piston pump
• Wet-bowl and dry-bowl operating modes
• Automatic vacuum breaker operated by the flush-control lever
• Spring-assisted top-valve closure for easier priming
• Constant 38mm waste path helps reduce blockages
• Full-bore joker valve provides automatic backflow control
• Multi-angle discharge elbow rotates through 360°
• Compatible with compact and regular-bowl toilets
• Suitable for right- or left-hand pump installations when the toilet is correctly configured
• Fits current Twist 'N' Lock and compatible earlier grey- and black-handle toilets
• Rectangular four-screw base mounting
• Designed for sea, river or lake water flushing systems
• No electrical supply required

What Is Supplied?

• Complete Twist 'N' Lock pump assembly
• Pump handle and piston mechanism
• Flush-control valve assembly
• Discharge elbow
• Joker valve installed within the discharge assembly
• Base valve gasket
• Spare screw for the discharge-elbow housing

The supplied base valve gasket is also identified separately by Jabsco as part number 29043-0000.

Pump Assembly or Service Kit?

Choose the Jabsco 29040-3000 pump assembly when the complete pump body, piston, handle, valves or discharge assembly needs replacement, or when upgrading a compatible older pump to Twist 'N' Lock operation.

The Jabsco 29045-3000 major service kit is a separate overhaul kit containing the principal wearing parts for the later pump design. It is intended for servicing an existing reusable pump assembly rather than replacing the complete unit.

Installation Guidance

• Close the inlet and discharge seacocks before beginning work
• Wear suitable protective gloves
• Place a bucket or tray beneath the toilet to collect residual water or waste
• Disconnect the bowl-rinse and flushing-water hoses
• Disconnect the discharge elbow or transfer the existing elbow and hose as one assembly
• Remove the four screws securing the pump to the toilet base
• Remove and replace the old base valve gasket
• Install the replacement pump with the Twist 'N' Lock handle in the unlocked position
• Tighten the mounting screws by hand without overtightening into the plastic base
• Rotate the discharge elbow as required before reconnecting the hoses
• Reopen the seacocks and check all joints for leaks

The base valve gasket must be installed in its keyed position with the raised section facing upwards. Installing the pump while locked can force the piston against the gasket and make correct assembly more difficult.

Important Compatibility and Safety Information

This pump is designed for compatible Jabsco manual marine toilets using sea, river or lake water for flushing. It must not be connected directly to a pressurised potable-water system.

The Twist 'N' Lock mechanism is an additional backflow safeguard. It is not a substitute for correctly installed and closed seacocks, vented loops or compliant marine sanitation plumbing.