Gecko AquaFlo FMXP2 Wet End (4.0HP, 6.3″) – 91041635

Product Overview

As a retailer of hot tub spare parts, I’m featuring this ultra-high-performance Gecko AquaFlo FMXP2 wet end, specifically engineered for 6.3″ configurations. This premium 4.0HP model represents the absolute pinnacle of power in the FMXP2 series.

Key Features

• Maximum-output 6.3″ configuration
• 2″ MBT (Male Buttress Thread) connections
• 56 frame compatibility
• Commercial-grade construction
• Precise bolt pattern design
• Complete component assembly

Technical Specifications

Specification	Detail
Model Number	91041635
Horsepower Rating	4.0 HP
Frame Size	56 Frame
Connection Size	2″ MBT
Bolt Pattern	6.3″ (4-1/8″ top bolt spacing)
Housing Diameter	6.3″
Construction	Industrial-grade materials
Design Type	FMXP2 Series
Top Bolt Spacing	4-1/8″
Build Type	Commercial-grade construction

Critical Sizing Note

This is specifically a 6.3″ wet end with precise measurements:

• Top bolt spacing: 4-1/8″ (6.3 designation)
• NOT compatible with 6.1 systems (4″ spacing)
• Complete pump replacement required if 6.1 sizing needed

Compatibility Information

• Specific to 56 frame motors
• 6.3″ configuration only
• 2″ plumbing systems
• FMXP2 series design
• 4.0HP ultra-high-performance applications

Important Installation Notes

• Critical to verify exact bolt pattern measurements
• Confirm 6.3″ specification match
• Check frame size compatibility
• Ensure proper alignment
• Follow mounting guidelines

Application Use

Ideal for:

• Commercial spa installations
• Ultimate flow requirements
• Large-scale systems
• Maximum-demand applications
• Professional installations
• Multiple high-flow jet configurations

Measurement Verification

Before ordering, confirm:

• Top bolt spacing (must be 4-1/8″)
• Overall housing diameter
• Frame size requirements
• Motor compatibility
• Plumbing specifications

What is a Wet End for a hot tub pump?

The "wet end" of a hot tub pump is a critical component that houses the impeller, seals, and volute. It's the part of the pump that is in direct contact with the water circulating through the hot tub. The wet end plays a key role in the hydraulic function of the pump, which is responsible for drawing water from the hot tub, pressurizing it, and then pushing it back into the spa through the jets.

Here are the main components of a hot tub pump's wet end:

1. Impeller: The impeller is a rotating blade or disc inside the wet end. When the pump is activated, the impeller spins, creating a flow of water. The design and size of the impeller significantly affect the water flow and pressure in the hot tub.
2. Volute: The volute is the curved, snail shell-shaped housing that surrounds the impeller. It directs the flow of water as it enters and exits the impeller. The volute's design influences the pump's efficiency and performance.
3. Seals and Gaskets: Seals and gaskets in the wet end prevent water from leaking out of the pump and into the motor or electrical components. Proper seals are crucial to maintaining a water-tight and safe operation.
4. Inlet and Outlet Ports: The wet end has inlet and outlet ports where plumbing connections are made. These connections are responsible for drawing water in and pushing it out to the spa's jets.
5. Motor Mounting Bracket: The wet end is typically connected to the pump motor with a mounting bracket. The motor provides the power to drive the impeller and create water circulation.

When a hot tub pump experiences issues, such as reduced flow or leaks, it often necessitates maintenance or replacement of the wet end. Replacing the wet end is an effective way to address problems without having to replace the entire pump motor. When choosing a replacement wet end, it's essential to ensure compatibility with the existing motor, frame size, and plumbing connections to maintain the pump's proper operation.

What are the top 10 considerations for finding a replacement wet end for a hot tub pump?

Finding a replacement wet end for a hot tub pump is an important part of fixing your hot tub - if you are looking for a replacement wet end it has broken, cracked or seized I am sure. Here are the key considerations when searching for a suitable replacement:

1. Pump Model and Brand Compatibility: The most critical consideration is ensuring that the replacement wet end is compatible with your hot tub's pump model and brand. Look for the same make and model or a compatible alternative from the same manufacturer.
2. Wet End Size: Pay attention to the wet end's physical dimensions, such as its height, width, and depth, to ensure it fits your existing pump housing. Measure the old wet end if necessary.
3. Plumbing Connections: Confirm that the replacement wet end has the same plumbing connections (inlet and outlet sizes and types) as your current wet end. Mismatched connections can lead to leaks and reduced efficiency.
4. Impeller Size and Type: Check the size and type of the impeller included with the replacement wet end. It should match the impeller you currently have or be compatible with your pump's horsepower rating.
5. Horsepower Rating: Ensure that the replacement wet end matches the horsepower rating of your existing pump. Using a wet end with the wrong horsepower can lead to inefficient operation or damage to the pump.
6. Material and Durability: Consider the material of the wet end and its durability. Wet ends are typically made of plastic or thermoplastic materials, which are corrosion-resistant. High-quality wet ends may have reinforced construction for added durability.
7. Seals and Gaskets: Check if the replacement wet end includes seals, gaskets, and O-rings. Proper seals are essential to prevent leaks and maintain water-tight connections.
8. Thread Type: Verify the thread type of the wet end, as it must match your existing pump's threads for a secure connection.
9. Frame Size - Check that you are replacing the right frame size or the bolts will not match and line up.
10. VISUAL INSPECTION - make sure that the wet end that you are buying looks EXACTLY like the wet end you want to replace.

What are the different Frame Sizes of Hot Tub Pumps?

Hot tub pumps come in various frame sizes to accommodate different motor configurations and horsepower ratings. The frame size is a crucial factor in ensuring the compatibility of a pump with your hot tub's existing setup. Here are the most common frame sizes for hot tub pumps:

1. 48-Frame:
   • The 48-frame pump is one of the most common frame sizes for hot tubs. It's known for its compact design and is often used in smaller hot tubs or those with lower horsepower requirements. These pumps typically have a smaller footprint, making them suitable for tight spaces.
2. 56-Frame:
   • The 56-frame pump is a larger and more powerful option. It is commonly used in mid-sized to large hot tubs with higher horsepower motors. These pumps offer enhanced performance and durability and are more energy-efficient.
3. 48Y-Frame and 56Y-Frame:
   • These frame sizes are variations of the 48-frame and 56-frame pumps, respectively. They are designed with specific motor mounts and configurations to fit certain hot tub models or brands. It's essential to match the frame size and motor type precisely when replacing these pumps. The "Y" portion means that something is not standard and it usually pertains to the mounting configuration. For example, it might not come with actual feet.
4. 42-Frame:
   • While less common, 42-frame pumps are used in some older hot tub models. These pumps are smaller and less powerful than 48- and 56-frame pumps. Finding replacement parts for 42-frame pumps can be more challenging due to their limited availability.
5. Motor Frame Adapters:
   • In some cases, you may encounter hot tub pumps with frame adapters. These adapters allow you to retrofit a pump with a different frame size to fit your specific hot tub model. They can be a solution when you can't find an exact frame size match.

When selecting a replacement pump or performing maintenance on your hot tub, it's crucial to match the frame size, motor configuration, and horsepower rating to your existing pump. An exact match ensures that the pump fits correctly and operates efficiently. If you have any doubts about which pump to choose or how to replace an existing one, consider consulting a professional hot tub technician who can provide guidance and perform the installation correctly.

How do you replace a Wet End?

Wet End Replacement - The wet end in your spa pump is the part that comes into contact with water, consisting of the volute halves, impeller, and shaft seal. It's available as a complete unit, allowing for swift on-site replacement in the event of volute, impeller, or seal issues.

Here's a quick guide for changing the wet end on a 56-frame Ultramax spa pump.

Step 1: Start by removing all the bolts securing the volute or impeller housing from the front of the wet end. The number of bolts may vary, typically being either five or six.

Step 2: Insert a slotted screwdriver into the rear of the motor shaft, potentially requiring you to remove a cover plate, to keep the shaft stationary. Now, carefully turn the impeller counterclockwise to remove it. If it's stuck, you can use a pair of large Channel Lock pliers to assist in the removal. Having a second person hold the screwdriver on the rear of the motor shaft can also be helpful.

Step 3: Once the impeller is off, take note of the color bands on it, indicating the impeller's horsepower. Ensure it matches the motor's hp and corresponds with your new wet end.

Step 4: Next, remove the four motor bolts by loosening them with a 5/16" nut driver, freeing the tank from the motor. If the motor shaft is in poor condition (rusty, dusty, or crusty), clean it with some sandpaper.

Step 5: Your replacement seal should already be in place within the new wet end. Confirm that the color bands align with the correct horsepower for your motor.

Step 6: Position the new wet end over the shaft, ensuring it aligns in the same orientation as your previous wet end, either pointing up or to the side.

Step 7: Use a slotted screwdriver at the back of the motor shaft to turn the shaft, pulling the new wet end tightly against the motor. This action threads the shaft into the impeller and compresses the spring.

Step 8: Insert the motor bolts and hand-tighten them all the way. Then, use a 5/16" nut driver to securely fasten them in a diagonal cross pattern. Reach into the front of the new wet end to confirm that the impeller spins freely.

Step 9: Reconnect the wiring and the union connectors, completing the wet end replacement. Your spa pump should now be ready for use.