BENNETT MARINE M80 M120 Sport Tab Instruction Manual
- June 13, 2024
- Bennett Marine
Table of Contents
M80 / M120 Sport Tab
Installation Instructions
M80 M120 Sport Tab
For information on installing Bennett helm controls, please visit BennettTrimTabs.com/Installation or call (866 894 626-1 .)
Items Included in Sets
Materials & Tools Needed
• Wire Stripper
• Wire Cutters
• 3/32″, 3/16″, 5/32″ &3/4″ Drill Bits
• 1/2″ & 7/16″ Wrenches| • Tape Measure
• Automatic Transmission Fluid
• Small Funnel
• Electric Drill| • #2 & 3 Phillips Screw Drivers
• 2-ft. Straight Edge
• 3M 5200 Marine
Grade Sealant
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Basic System Diagrams
Mounting Options
Step 1: TRIM TAB & ACTUATOR INSTALLATION
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 the tabs
3″ to 4″ from the chine (side of boat) and run them towards the centerline of
the boat (See Fig. 1). Boats with outboard motors or inboard/outboards (I/Os)
must maintain a minimum of 8″ from the centerline of outboard or stern drive
unit to the closest edge of the trim tabs. Boats with inboard motors may
utilize the entire run of the transom.
Note: If the inside of the transom is inaccessible due to fuel tank,
flotation, or other obstruction, call Bennett Marine for alternate
installation options at 866-894-1626.
For Boats Kept In Salt Water: To provide protection from electrolytic
corrosion, a zinc anode must be applied to each tab. Do not ground tabs to
other underwater appendages. Failure to provide zinc anode protection can
result in the trim tabs being quickly damaged by electrolysis. Call Bennett
Marine for more information. Step 2
Attach the mounting plates and trim tab 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. Drill the mounting plate holes using a
5/32″ drill bit. Assemble backing plates and hinge plates, dip screws in 3M
5200 (or equivalent marine epoxy) before running in. 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 x 1-1/4″
self-tapping stainless steel screws. If the transom is curved, a shim must be
made of a suitable material to provide a flat mounting surface (see figure 3
on the previous page). Call Bennett Marine for more information.
Instructions continued on the rear page…
Step 3
Secure the lower hinge of each actuator to the tab with the 1/4-20 x 3/4″
Phillips head machine screws. Using a straight edge under the hull bottom, set
the “negative angle” of the tab’s trailing edge with a negative angle of 5/8″
(See figure 4.)
Step 4
With tabs set at a 5/8″ negative angle, position the upper mounts of the
actuators against the transom. Slide the attached actuator template (see
reverse page) behind upper mount, align and tape to 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 5). The
straight edge may now be removed. Drill holes accurately as indicated on
templates. Drilling a small pilot hole first helps you locate accurate
centers.
Step 5
Screw the brass fitting with the 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 figure 6)
Step 6
Feed the taped end of the tubing through the 3/4″ hole in the transom. Apply
sealant on the mounting surface of the actuators and around the brass fitting.
Secure the actuator upper to the transom with the #14x x 1/12″ screws.
Step 7: INSTALLING THE HPU
Remove plug from filler stack located at the front left corner of the
reservoir. Fill the reservoir to “Full Line” using any type automatic
transmission fluid (ATF). 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 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 lower screws and secure bracket. Slide HPU into
bracket.
Step 8 With plastic hangers or cable ties, secure hydraulic tubing along
hillside or bulkheads to HPU. Make the port and starboard hydraulic tube
lengths as equal as possible. When facing HPU, the brass fitting on the left
of the pump face connects with the tubing from the port actuator, the fitting
on the right connects with tubing from the starboard actuator. These fittings
are identified “P” & “S” for port and starboard by small letters directly
above each one. To connect tubing to the pump, insert tubing through the nut
with ferrule fitting and push into the pump-face fitting until it bottoms.
While continuing to bottom the tubing in the fitting, tighten nut “finger
tight,” then one full turn with a 1/2″ wrench … no more. Use the tube bending
clip at desired 90 degree bends in the tubing to prevent kinking. Connect the
HPU ground wire to any convenient ground. Then run the wiring harness from the
HPU to the helm.
Step 9: INSTALLING THE HELM CONTROL
The M80/M120 Sport Tab kits are available with various helm control options.
Please follow the helm control instructions included with your particular kit.
Helm control installation manuals can also be found at
BennettTrimTabs.com/Install.
Step 10: BLEEDING THE SYSTEM
Using the control, hold 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. Place both trim tabs in the full down position and
check the hydraulic system for leaks. Bring the tabs in full up position and
check fluid level. Add ATF if necessary.
Have questions?
We’re here to help.
Call us at866-894-1626 for
assistance.