Furuno LS-4100 Operator's Manual page 37

Warning: Always wear safety
goggles and a dust mask.
3. Using a 4 mm, #23, or 9/64" bit, drill
three holes 22 mm (7/8") deep
at the locations indicated. To prevent
drilling too deeply, wrap masking
tape around the bit 22 mm (7/8")
from the point.
Fiberglass hull: Minimize surface
cracking by chamfering the gelcoat.
If a chamfer bit or countersink bit is
not available, start drilling with a
6mm or 1/4" bit to a depth of 1 mm
(1/16").
4. If you know your transom angle, the
bracket is designed for a standard
13° transom angle.
11°-18° angle: No shim is required.
Skip to step 3 in "Adjusting".
Other angles: The shim is required.
Skip to step 2 of "Adjusting".
If you do not know the transom angle,
temporarily attach the bracket and
sensor to the transom to determine if
the plastic shim is needed.
5. Using the two #10 x 1-1/4"
self-tapping screws, temporarily
screw the bracket to the hull. DO
NOT tighten the screws completely
at this time. Follow the step 1-4 in
"Attaching the Sensor to the Bracket",
before proceeding with "Adjusting".
Adjusting
1. Using a straight edge, sight the
underside of the sensor relative to
the underside of the hull. The stern
of the sensor should be 1-3 mm
(1/16-1/8") below the bow of the
sensor or parallel to the bottom of
the hull.
2 -10 11 transom angle
transom
angle
shim with
taper down
YES
parallel
12-18 transom angle
NO
angle
reversed
Sensor position and transom angle
Note: Do not position the bow of the
sensor lower than the stern because
aeration will occur.
2. To adjust the sensor's angle relative
to the hull, use the tapered plastic
shim provided. If the bracket has
been temporarily fastened to the
transom, remove it, Key the shim in
place on the back of the bracket.
2°-10° transom angle (stepped
transom and jet boats): Position
the shim with the tapered end down.
19°-22° transom angle (small
aluminum and fiberglass boats):
Position the shim with the tapered
end up.
3. If the bracket has been temporarily
fastened to the transom, remove it.
Apply a marine sealant to the
threads of the two #10 x 1-1/4" self
tapping screws to prevent water
seeping into the transom. Screw the
bracket to the hull. Do not tighten the
screws completely at this time.
31
19 -22
NO SHIM transom
angle
shim with
taper up
YES
parallel parallel
NO SHIM
YES
slight angle
angle too steep
YES
NO