M80/M120 fitting instructions

M80 / M120 Fitting Instructions

Please read instructions completely before beginning installation

These installation instructions are for M80 and M120 Sport Tab kits only.
Please contact us for installation instructions for other Bennett kits.

Tools and Materials List:
7/16", 1/2" Wrench    Small Funnel
Electric Drill    Wire Stripper
Two Foot Straightedge    1 1/8" Hole Saw
Marine Grade Sealant    Tape Measure
Masking Tape    Wire Cutters
9/64", 3/32", 5/32", 3/16", and 3/4" Drill Bits    #2 and 3 Phillips Head Screwdriver
Automatic Transmission Fluid    Regular Flat Head Screwdriver
Step 1 - Position the trim tabs against the transom and check to see that the upper mounts of the hydraulic actuators do not center on an inside obstruction. If they do, reposition the tabs slightly outboard. The further outboard the tabs are mounted the greater the lateral (side to side) control. Position tabs 3 to 4 inches from the chine, and a minimum of 8" from the centerline of the outboard or sterndrive unit (see Picture 1 and Figure 1). Note: If the inside of the transom is inaccessible due to a fuel tank, flotation, or other obstruction, contact us for alternate installation options.

Picture 1

Figure 1 (click for larger image)

Step 2 - Attach the mounting plates and trim plane with #10 x 1-1/4" stainless steel screws 1/4" above the hull bottom (see Figure 2). Using the backing plate as a template, mark screw hole locations (see Picture 2 and Picture 3). Drill 9/64" pilot holes for mounting screws. Test to see how the screws fit. Enlarge with 5/32" drill if needed. Assemble mounting plates and tap, dip screws in marine epoxy before tightening them. Slide trim tab between backing plate and hinge plate before running screws tight. Snug screws down to secure mounting plates and trim tab to transom. Aluminum boats should use machine screws and nuts (not included) instead of the enclosed #10 self-tapping screws.

Figure 2 (click for larger image)

Picture 2

Picture 3

Step 3 - Secure the lower hinge of the actuator to the port trim tab using 1/4-20 x 3/4" machine screws. Using a straightedge under the trim tab and hull bottom, set the corner of the tab trailing edge to 5/8" negative (see Figure 2 and Picture 4). With the tab set at this 5/8" negative angle, position the upper mount of the actuator against the transom. Slide the actuator template behind the upper mount, align and tape to the transom. It is not necessary that the upper mounts lie flat against the transom as the actuator neck has the ability to flex far more than necessary (see Figure 3). The straightedge may now be removed. Drill holes accurately as indicated on templates. Drilling a small pilot hole first helps you locate accurate centers. Repeat for the starboard side.

Picture 4

Figure 3

Step 4 - Screw brass fitting with attached tubing into the upper mount of the actuator. Tighten the fitting only snug with a 7/16" wrench. Do not attempt to "bottom out" the fitting (see Picture 5 and Figure 4).

Picture 5

Figure 4

Step 5 - Feed the taped end of the tubing through the 3/4" hole in transom. Apply sealant on the mounting surface of the actuators and around the brass fitting. Secure the actuator upper mounts to transom with #14 x 1-1/2 " screws. (See Pictures 6 and 7)

Picture 6

Picture 7

Step 6 - Install Hydraulic Power Unit (HPU) in a convenient location with a dry environment. Important: The HPU must be mounted in a dry enough location to avoid submersion and drenching. Allow some space above the HPU so that it may be slid into its mounting bracket (about 3"). Lay out upper holes on HPU mounting bracket 4-5/8" apart and start #10 x 1" screws using 5/32" pilot holes. Then drill 5/32" pilot holes for the lower screws and mounting bracket. Fill HPU reservoir to full line using any type of automatic transmission fluid (ATF). Slide HPU into bracket. (See Pictures 8 and 9).

Picture 8

Picture 9

Step 7 - Connect black HPU ground wire to any convenient ground.

Step 8 - Run hydraulic tubing along hullside or bulkheads to HPU. Note: Make port and starboard tubing runs as equal as possible. When facing HPU, the brass fitting on the left side of the pump face connects with tubing from the port actuator, and the fitting on the right connects to the starboard actuator. These fittings are marked "P" and "S" for port and starboard. To connect tubing to the pump, insert tubing in the fitting and tighten nut finger tight, then one full turn with a 1/2" wrench. NO MORE. Use tube bending clips at desired 90 degree bends in tubing to prevent kinking.

Step 9 - Choose a spot on at your helm to mount the Rocker Switch Control. Using the included plastic drill guide template, drill four 3/16" holes and follow with a 1-1/8" diameter hole saw. (See pictures 10 and 11). These holes must be 1-1/16" on center in both directions. The Rocker Switch Control will fit into this hole. We strongly suggest that this first be tried on a practice piece of wood.

An alternate way to mount your control is to cut a rectangular hole with rounded (1/2" radius) corners 1-3/4" W x 2-1/8" H. Note that the control switch attaches to the corners, so be careful not to cut away the mounting area.

Picture 10

Picture 11

Step 10 - Pull the wire harness up through the hole and attach it to the back of the switch with the ring connectors enclosed. There are two screws per letter; the wire can be attached to either screw fastening on the brass strip marked with the first letter of the color of the wire* (see Figure 5 and Picture 12).

Figure 5

Picture 12

Blue wire = Pump pressure (tabs down)
Yellow wire = Pump retract (tabs up)
Red wire = Port valve
Green wire = Starboard valve

Step 11 - Mark the four locations for the 7/64" pilot holes and drill each (see Figure 5). (Test #8 screw. Open hole to 1/8" if necessary). Apply sealant compound around underside of switch plate assembly being careful not to block weep holes.

Step 12 - Place the wire harness and switch back in the hole and mount the switch plate assembly with the enclosed #8 screws. Be sure the switch is properly seated and snap bezel onto switch plate assembly. Note: Bezel will secure completely when BOW DOWN is at the top and the switch plate assembly is mounted with top and bottom in proper position. (See Picture 13)

Picture 13

Step 13 - Connect fused (20 amp) orange power lead from Rocker Switch to 12 volt power source.

Step 14 - Using the Rocker Switch Control, press the "Bow Down" position for 15 seconds, then "Bow Up" for 15-20 seconds. Repeat 3 times. This will purge any air from the system. No bleeding is necessary.

Step 15 - Place both trim tabs in the "full down" position and check the hydraulic system for leaks. Bring the tabs to the full up position and check fluid level. Add ATF if necessary.