Moeller Sending Unit: Screw Size And Compatibility Guide

Moeller Marine offers a range of sending units for boats, which are easy to install and are suitable for gasoline, ethanol, diesel, and non-potable water. The Moeller sending unit is calibrated to the industry standard of 33-240 ohms and comes with a 5-hole gasket and screws. The unit's float arm can be adjusted to clear the tank wall by turning the screw assembly in 90-degree increments. The proper float arm length can be determined by measuring the tank depth and ensuring at least 1 of arm overlap at the clamp assembly point. It is important to note that the gasket should be aligned correctly, as the screw hole pattern is not symmetrical. While the sending unit is generally well-received, some customers have reported issues with the accuracy of the fuel gauge readings and the fit of the gasket and screws.

Moeller sending unit calibration

Moeller Marine offers a range of sending units for initial installation or to replace existing units. These sending units are suitable for gasoline, ethanol, diesel, bio-diesel, and non-potable water. They are fire-rated and meet various industry standards.

All Moeller sending units feature a calibration of 33-240 ohms, a 5-hole gasket, and are compatible with a dash-mounted gauge. The calibration process involves adjusting the float arm to the correct position and ensuring the correct wiring connections are made.

For example, one user who installed new Moeller Reed Switch fuel sending units in their boat described their calibration process. They connected the white wires from the sending units to the Fuel 1 and Fuel 2 wires at the back of the tach gauge. They set the source to "Sender" and selected the "US 33-240 ohm" setting. However, they encountered an issue where neither tank was registering any level.

To troubleshoot this issue, the user was advised to check the settings in the Data Sources menu and ensure they had selected the correct tank type and capacity. They were also advised to confirm the settings in the separate Data Sources menu where "Sender" was not an option.

Another user shared their experience with a Moeller fuel gauge, which involved a manual calibration process. They used a two-foot-long dowel to check the fuel level and found that the gauge was inaccurate when the tank was less than half full. This highlights the importance of properly calibrating Moeller sending units to ensure accurate fuel level readings.

Overall, the calibration process for Moeller sending units involves adjusting the float arm, making correct wiring connections, and verifying the settings in the gauge's menus. Proper calibration ensures accurate fuel level readings, which is crucial for boat safety and performance.

Moeller sending unit gasket

Moeller Marine offers a range of gaskets for their fuel tank sending units. The gaskets are designed for top mounting in aluminum, plastic, or stainless steel fuel tanks on all types of marine vessels. They exceed current NMMA and ABYC specifications and are calibrated to the industry standard of 33-240 ohms.

The Moeller Marine 035728-10 gasket is a 5-hole gasket designed for electric and mechanical fuel sending units. It comes with fine and coarse replacement screws and washers. This gasket has received positive reviews for its quality, performance, fit, ease of installation, and completeness. It is available on Amazon for $14.43.

The Moeller Marine electrical reed switch fuel sending unit is another product that comes with a gasket and screws. It is made of stainless steel and provides efficient performance. Fuel measurements are taken from the float, and the sender length is 1" shorter than the tank depth. This product has received positive reviews for its performance, ease of installation, quality, accuracy, and value. It is available on Amazon for $70.68.

In addition to the above products, Moeller Marine also offers a universal 5-hole pattern mounting gasket (part number MO-035728-10) that fits their electric and mechanical fuel sending units. This gasket includes 10/24 and 10/32 mounting hardware. It is available from Marine Parts Source for $10.50.

Moeller sending unit screws

Moeller Marine offers a range of sending units for initial installation or to replace existing units. These sending units are available in various designs, including mechanical, electrical, reed array, and reed switch operation. All Moeller sending units feature a 33-240-ohm calibration, a 5-hole gasket, and screws. The gasket and screws are included with the sending unit, making it ready for installation.

The sending unit's screws play a crucial role in ensuring a secure and proper fit. When installing the sending unit, it is important to align the screw hole pattern in the mounting flange with the hole pattern on the top of the tank. This alignment ensures that the sending unit is positioned correctly and securely attached to the tank.

To achieve the correct alignment, you may need to rotate the sending unit. This can be done by loosening the brass nut on top of the five-hole flange by approximately 1/8" (3.25 mm). Once the nut is loosened, gently push on the end of the screw while holding the mounting plate still. This action will dislodge the center square located at the screw base, allowing the assembly to move freely. From there, you can turn the screw assembly in 90° increments until the float arm clears the tank wall.

After achieving the correct alignment and positioning the float arm appropriately, the next step is to tighten the screws. It is important not to over-tighten the screws, as this can weaken the seal. Instead, tighten the screws just until white sealant begins to show beneath the screw head. To ensure a leak-proof installation, a leak test should be conducted by pressurizing the tank to 3 PSI and checking for bubbles using soapy water.

In addition to the gasket and screws, Moeller Marine also provides detailed instructions for installing their sending units. These instructions include important safety precautions, such as avoiding the use of power tools around fuel vapors, which are highly combustible. By following the provided instructions and properly tightening the screws, boaters can ensure a secure and safe installation of their Moeller sending units.

Moeller sending unit installation

Moeller offers a range of sending units for initial installation or to replace existing units. The sending units are available in mechanical, electrical, reed array, and reed switch operation designs. They are suitable for gasoline, ethanol, diesel, and bio-diesel, depending on the model.

Before installing a Moeller fuel gauge, ensure you have the necessary hand tools: a tape measure, torque wrench, Phillips-head screwdriver, and a hacksaw. It is important to avoid using power tools around fuel vapors, which are easily combustible.

• Remove the old unit if you are replacing an existing fuel sender. Note the direction of movement of the old float arm to assist with the installation of the new unit.
• Position the new unit above the tank, aligning the screw hole pattern in the mounting flange with the hole pattern in the top of the tank.
• Observe the direction of the float arm movement. If the arm position causes it to hit the tank wall, you must rotate the sending unit. If the arm moves freely, proceed to the next step.
• Rotate the sending unit by loosening the brass nut on top of the five-hole flange by approximately 1/8" (3.25 mm). Do not remove the nut completely.
• Gently push on the end of the screw while holding the mounting plate still. This will dislodge the center square located at the screw base, allowing the assembly to move freely.
• Turn the screw assembly in 90° increments until the float arm clears the tank wall. Then, push the mounting flange back onto the center square.
• Tighten the nut at the top of the sending unit to 15 inch-pounds using a torque wrench.
• Adjust the float arm length by measuring the tank depth and sliding the float arm through the float arm clamp assembly until the correct length is reached, ensuring at least 1" of arm overlap at the clamp assembly point.
• Mark the float arm placement and cut the float arm attached to the sending unit accordingly, leaving at least 2" of arm length attached to the sender.
• Secure the float arm into position by firmly tightening the assembly screw. Do not bend the float arm, as this could cause the sending unit to malfunction.
• Slide the gasket over the float arm and sending unit assembly. Align the 5-hole screw pattern in the gasket with the mounting flange, placing the gasket flush against the underside of the plate.
• Install the electric fuel sender by gently inserting the float arm into the tank, followed by the sending unit. Align the screw holes between the gasket, mounting plate, and tank.
• Secure the sending unit to the tank by tightening the mounting screws until white sealant appears beneath the screw head. Do not over-tighten, as this will weaken the seal.
• To ensure a leak-proof installation, conduct a leak test by pressurizing the tank to 3 PSI and checking for bubbles using soapy water.
• Connect the sender wire from the fuel gauge to the threaded screw terminal on the sender.
• Connect the ground wire to the 1/4" fasson terminal on the sender. Ensure the tank is empty, and the area is free from sparks and flames as gasoline is extremely flammable.

Moeller sending unit wiring

This guide will take you through the process of wiring a Moeller sending unit, with detailed instructions to ensure a safe and successful installation.

Before beginning any work, it is important to gather all the necessary hand tools for the installation. These include a tape measure, torque wrench, Phillips-head screwdriver, and a hacksaw. It is also crucial to avoid using power tools around fuel vapors, which are highly combustible.

Firstly, if you are replacing an existing fuel sender, carefully remove the old unit, taking note of the direction of movement of the old float arm. This will assist you when installing the new Moeller sending unit.

The next step is to position the new sending unit above the tank. Align the screw hole pattern in the mounting flange with the hole pattern at the top of the tank. Observe the direction of the float arm movement. If the arm position causes it to hit the tank wall, you must rotate the sending unit. This can be done by loosening the brass nut on top of the five-hole flange by approximately 1/8" (3.25 mm).

Once the sending unit is in the correct position, gently push on the end of the screw while holding the mounting plate still. This action will dislodge the center square located at the screw base, allowing the assembly to move freely. Turn the screw assembly in 90° increments until the float arm is situated to clear the tank wall. Then, push the mounting flange back onto the center square.

Now, you can tighten the nut at the top of the sending unit to 15 inch-pounds using a torque wrench.

The next step is to determine the proper float arm length. Measure the tank depth (from the inside bottom to the outside top of the tank) and subtract 1/2". For example, if your tank measurement is 24", the proper float arm length would be 23-1/2". Adjust the float arm length accordingly.

Slide the float arm through the float arm clamp assembly until you reach the correct float arm length, ensuring at least 1" of arm overlap at the clamp assembly point. Mark the float arm placement carefully before cutting. Leave at least 2" of arm length attached to the sender and cut any additional length from the arm attached to the float.

Secure the float arm into position by firmly tightening the assembly screw. Remember, do not bend the float arm, as this could cause the sending unit to malfunction.

Now, you are ready to install the gasket and mounting plate. Carefully slide the gasket over the float arm and sending unit assembly. Align the 5-hole screw pattern in the gasket with the mounting flange, ensuring the gasket is flush against the underside of the plate. Please note that the screw hole pattern is not symmetrical, so there is only one way to properly align the gasket.

Install the electric fuel sender by gently inserting the float arm into the tank, followed by the sending unit. Align the screw holes between the gasket, mounting plate, and tank. Secure the sending unit by tightening the mounting screws until white sealant shows beneath the screw head. Do not over-tighten, as this will weaken the seal.

To ensure a leak-proof installation, a leak test should be conducted. Pressurize the tank to 3 PSI and use soapy water to check for any bubbles, indicating a leak.

Finally, you can proceed with the wiring installation. Connect the sender wire from the fuel gauge to the threaded screw terminal on the sender. Connect the ground wire to the 1/4" fasson terminal on the sender. It is crucial to remember that gasoline is extremely flammable. Keep the tank area free from sparks and flames, and empty the tank of fuel and fumes before continuing with the installation.

Always refer to the specific instructions provided with your Moeller sending unit and seek professional assistance if you are unsure about any part of the procedure.

Frequently asked questions