NMEA1 Installation Instructions

Important Considerations

Warning: If the actuator stroke is less than 1" or more than 2-1/2", or if less than 1" of piston shaft is exposed when the actuator is fully retracted, has an external hydraulic connection, or has three rings molded on the cylinder body (see Figure 1), special sensor coils are required. Contact Bennett Marine.

Make all electrical connections with power off.

Test system before putting the boat back in the water.

Tools Required

1/2" & 7/16" Wrench, 5/16" Drill Bit, Teflon Tape, Marine Grade Sealant, Wire Stripper, Vise Grips, Electric Drill, Wire Cutter.

Installing New Upper Hinge with Sensor

1. Inside the transom, with trim tabs in the full up position, locate the trim tab hydraulic line and detach the tubing from the brass elbow. Expect some fluid to drip out. While holding the pipe nipples with vise grips, unscrew the brass elbow. Perform this procedure for both the port and starboard cylinders (see Figure 2). If no pipe nipple is visible inside the transom, you have a short fitting connection (see Figure 3); skip to Step 2.Figure 2: Diagram showing the process of detaching a hydraulic line from a brass elbow connected to a pipe nipple inside the transom. It illustrates holding the pipe nipple with vise grips while unscrewing the brass elbow.
2. Outside the transom, snap the white plastic clip onto the shaft protruding from the bottom of the cylinder. Grasp the cylinder body with both hands and unscrew it counterclockwise from the cylinder upper hinge. A small amount of fluid will spill.
3. Insert a metal rod into the piston, with the pointed end down. Ensure the O-ring is in place in the new upper hinge with the sensor coil. Screw the new upper hinge onto the cylinder while keeping the metal rod inserted into the center of the sensor coil. The red cable is for the port side, and the green cable is for the starboard side. Tighten the upper hinge hand tight. IMPORTANT: Use care when handling sensor coils during assembly to avoid damaging wires.
4. Remove the upper hinge from the transom and remove the pipe nipple. If you have a short fitting, use a 7/16" wrench to remove it from the upper hinge.
5. Remove the plastic clip from the piston and repeat steps 2 through 4 for the starboard cylinder.
6. Using the provided template, drill a 5/16" hole in the transom for the sensor cable. Screw the pipe nipple into the new actuator upper hinge. Tighten the nipple hand tight. Then, using vise grips, tighten it two full turns – no more. If you have the short fitting, use a 1/2" wrench to screw it in until the fitting is snug, ensuring the shoulder of the fitting just touches the plastic of the upper hinge.Diagrams showing precise measurements for drilling holes in the transom for sensor cable and mounting screws. One diagram indicates a 5/16 inch hole for the sensor cable and a 3/4 inch spacing for mounting screws, with 3/16 inch offsets. Another diagram shows hole placement for the upper hinge with dimensions like 5/16 inch and 3/16 inch.
7. Cover the end of the pipe nipple with masking tape. Apply sealant to the actuator upper hinge surface around the pipe nipple, screw holes, and cable. Feed the actuator cable through the 5/16" hole and secure the actuator upper hinge to the transom with mounting screws. Grasp the cylinder body with both hands and tighten it securely clockwise. Repeat for the other side. Run cables to the helm.
8. Inside the transom, remove the masking tape from the pipe nipples. Carefully wrap Teflon tape around the male threads of the pipe nipples. Holding the pipe nipples with vise grips (to prevent them from turning), re-secure the 90-degree elbows. Re-attach the hydraulic tubing, tightening the nut finger tight. Snug the nut with a 1/2" wrench. Do not over-tighten. Note: If you have the short fittings, omit this step.

Wiring NMEA1 to NMEA2000 Backbone

1. Using red butt connectors, splice the red and green wires from the sensors to the red and green wires from the NMEA1 module. Note that either red or green wire from the sensor may be spliced to either red or green wire from the NMEA1 module.
2. Run the connection cable from the NMEA1 Module to the Backbone cable of your NMEA2000 system.
3. Connect the cable into the Backbone using a red Device Net "T" (not included). You will need to purchase this "T" or buy an adapter to fit your current NMEA2000 system. Please contact your electronics manufacturer.
4. Make sure the Backbone system has the correct terminator in place.
5. Your NMEA1 Trim Tab position sensor is now installed. Refer to the Lowrance, or other electronics manufacturer's instructions for calibration of the system.

Product Support

For product support, please call 1-866-894-1626 (Option #3), or email BMI_Info@Yamaha-motor.com.

Bennett Marine is a Division of Yamaha Marine Systems Company, Inc. Learn more at BennettTrimTabs.com.