Raymarine L750 User manual

Distributed by
Any reference to Raytheon or
RTN in this manual should be
interpreted as Raymarine.
The names Raytheon and RTN
are owned by the
Raytheon Company.

L750 Fishfinder
Operation Handbook
Raymarine

Contents i
Contents
Chapter 1: Introduction.................................................................. 1
AbouttheL750Fishfinder ........................................................ 1
System Components ............................................................... 1
StandardEquipment .......................................................... 1
StandardTransducers ....................................................... 2
OptionalAccessories ......................................................... 2
Chapter 2: Installation.................................................................... 4
AbouttheTransducer .............................................................. 4
SelectingtheCorrectTypeofTransducer.................................. 5
InstallingaThru-HullTransducer .............................................. 6
BeforeYouBegintheInstallation......................................... 7
SelectingtheBestLocationfor the Transducer..................... 7
MountingtheFairingBlock ................................................. 8
InstallingaThru-HullTransducer....................................... 10
AssemblingtheTransducerBracket.................................. 11
PositioningtheTransom-Mount Transducer ...................... 12
Mounting the Transom-Mount Transducer......................... 13
MountingtheOptionalSidelookerTransducer ................... 15
InstallationNotes–In-HullTransducer .............................. 16
InstallationNotes–TrollingMotor Transducer.................... 17
InstallationNotes–TransducerforSpeedand
Temperature Only............................................................ 17
EMCInstallationGuidelines ................................................... 17
MountingtheDisplayUnit....................................................... 19
StandardMount ............................................................... 19
FlushMount .................................................................... 19
InstallingtheTransducerCable .............................................. 21
Thru-HullandTransom-Mount Installation ......................... 21

L750Fishfinder:InstallationandOperationHandbook
ii
SidelookerOption ............................................................ 22
InstallationwithSeparateSpeedand
Temperature Sensors ...................................................... 23
MakingtheDCPowerConnections ........................................ 23
CalibratingtheSensors.......................................................... 25
Chapter 3: Operating Instructions ............................................... 27
ControlsonDisplayUnit ......................................................... 27
TurningthePower On andOff ................................................ 30
TurningthePowerOn–InitialUse .................................... 30
TurningthePowerOn–Routine Operation........................ 31
TurningthePower Off ...................................................... 31
SetupMemory and Master Reset ........................................... 32
OperatingPages ................................................................... 32
DownlookPage ............................................................... 33
FishIndications................................................................ 37
BottomIndications ........................................................... 38
WindowPage .................................................................. 39
DigitalPage ..................................................................... 41
ModifyingDisplays ................................................................ 42
FrequencySoftKey ......................................................... 42
ZoomSoftKey................................................................. 44
BottomLockSoftKey ....................................................... 47
A-Scope(Bottom Coverage)Key ...................................... 49
OtherControl Buttons ............................................................ 50
Display............................................................................ 50
Gain/Sensitivity ............................................................... 50
Range............................................................................. 52
VRM ............................................................................... 53
Multi-purpose .................................................................. 54

Contents iii
Alarms ............................................................................ 55
Mark ............................................................................... 57
AbouttheSidelookerFeature ................................................. 58
TheSidelookerPage........................................................ 59
TheSplit-ScreenSidelookerPage .................................... 61
Turning OntheSidelookerFeature................................... 61
SettingtheSidelookerRange ........................................... 61
SettingtheSidelookerGain/Sensitivity .............................. 62
Chapter 4: Setup Instructions ...................................................... 63
TheSetup Menus .................................................................. 63
ChartSpeedSetting......................................................... 63
LogReset........................................................................ 64
SystemSetup Menu ........................................................ 64
ResettingtheUnittoFactory Defaults ..................................... 68
DefaultSettings..................................................................... 68
Chapter 5: Maintenance and Troubleshooting ............................ 69
CleaningInstructions ............................................................. 69
TroubleshootingSuggestions................................................. 69
ServicingaThru-HullTransducer ........................................... 73
HowtoContactRaymarine .................................................... 73
PartsListing .......................................................................... 75
Chapter 6: Specifications ............................................................ 78
General Information............................................................... 78
FishfinderFunctions .............................................................. 78
ConnectorDiagram ............................................................... 79
Dimensions........................................................................... 80
Glossary of Terms ....................................................................... 81

L750Fishfinder:InstallationandOperationHandbook
iv
Figures
Fig.2-1 TransducerTypes................................................... 4
Fig.2-2 Thru-HullTransducer .............................................. 6
Fig.2-3 BestTransducerLocations ...................................... 8
Fig.2-4 InstallingaFairingBlock .......................................... 9
Fig.2-5 MountingtheTransducer Correctly ........................ 11
Fig.2-6 AssemblingtheTransducer Bracket....................... 11
Fig.2-7 Transducer Mounted onTransom.......................... 12
Fig.2-8 TransducerBracket,SideView.............................. 13
Fig.2-9 CorrectMountingPosition ..................................... 14
Fig.2-10 Mountingthe Transducer ...................................... 15
Fig.2-11 InstallingtheSidelookerTransducer....................... 16
Fig.2-12 SuppressionFerrites............................................. 18
Fig.2-13 MountingtheDisplay............................................. 19
Fig.2-14 Flush-MountInstallation ........................................ 20
Fig.2-15 InstallingCableonTransom .................................. 22
Fig.2-16 CableforSidelookerTransducer............................ 23
Fig.2-17 CableforSpeedandTemperature Sensor ............. 23
Fig.2-18 DCPowerConnections ......................................... 25
Fig.3-1 DisplayPanel ....................................................... 27
Fig.3-2 DisplaySoftKeys.................................................. 32
Fig.3-3 DownlookPage .................................................... 33
Fig.3-4 FishIndications..................................................... 37
Fig.3-5 BottomConditions ................................................ 39
Fig.3-6 Window“A”Page.................................................. 40
Fig.3-7 DigitalPage.......................................................... 41
Fig.3-8 FrequencySoftKeys............................................. 42

Contents v
Fig.3-9 SplitFrequencyFeature ........................................ 43
Fig.3-10 ZoomFeature On ................................................. 45
Fig.3-11 ZoomSoft Keys .................................................... 46
Fig.3-12 BottomLockDisplay ............................................. 48
Fig.3-13 BottomLockSoftKeys .......................................... 48
Fig.3-14 DownlookPagewithA-Scope................................ 49
Fig.3-15 GainorSensitivitySoftKeys .................................. 52
Fig.3-16 RangeSoftKeys................................................... 53
Fig.3-17 VariableRangeMarker ......................................... 53
Fig.3-18 Multi-PurposeSoftKeys........................................ 54
Fig.3-19 AlarmSoftKeys.................................................... 55
Fig.3-20 MarkDisplay ........................................................ 57
Fig.3-21 SidelookerFeature ............................................... 58
Fig.3-22 SidelookerPage ................................................... 59
Fig.3-23 Window“D”PagewithSidelookerInformation ........ 61
Fig.4-1 MenuSoftKeys .................................................... 63
Fig.4-2 ChangingtheChartSpeedSetting ......................... 63
Fig.4-3 SystemSetup Menu ............................................. 65
Fig.6-1 ConnectorDiagram .............................................. 79
Fig.6-2 Dimensions .......................................................... 80

L750Fishfinder:InstallationandOperationHandbook
vi

Chapter1:Introduction 1
Chapter 1: Introduction
About the L750 Fishfinder
The L750 Fishfinder is a system that uses sound waves (“sonar”) to
detectfishandshowthebottomofa lake or sea. The systemincludesa
transduceranda display unit,connectedby a cable. Thetransducer
sends high-frequency sound waves down into the water. These sounds
strikefish,thebottom, orotherobjectsinthewater,andreturnas
echoes. TheFishfindertheninterprets these echoesandpresentsa
display.
TheL750Fishfindercanhandlemanydifferentjobs:
•detectthepresenceoffishbelowtheboat
•triggeranalarmwhenfisharefound
•measurethedepthofthewater
•setalarmsforminimumandmaximumdepth
•showtheshapeofthebottom
•determinewhethertheseabedishardorsoft
•measurethespeedoftheboatandthedistancetraveled
•showthewatertemperature
WearesureyouwillfindtheL750Fishfindertobeoneofthemostuseful
devices on your boat.
System Components
TheL750Fishfinderconsists of acompactdisplay unit connectedtoa
transducer. Thetransducerisattachedtotheboat and extendsintothe
water.
StandardEquipment
WhenyouunpackyourL750Fishfinder,youshouldfindthefollowing
standardequipmentinthecarton. Ifanyitemsaremissing,pleasenotify
yourRaymarinedealer immediately, orcontact the CustomerService
DepartmentatRaymarineat1-800-539-5539,ext.2333. Pleaseprovide
theserialnumberoftheFishfinderwhenreportinganymissingitems.

L750Fishfinder: Installation andOperationHandbook
2
Description Part No.
L750 Fishfinder display unit M78956
Sun cover D331
Bracket assembly W143
Two trunion knobs W145
Three #8 x 3/4”mounting screws G625774-1
Transducer adapter cable G625877-1
DC power cable W144
Instruction manual G625773-2
Quick reference guide G626492-1
StandardTransducers
DependingonwhichmodeloftheL750youhavepurchased,theboxwill
includeoneofthetransducerslistedbelow:
Description Part No.
Transom-mount transducer (with speed
and temperature sensors, including
mounting bracket and hardware) M78898
Bronze thru-hull transducer (with
speed and temperature sensors) M78923
Optional Accessories
Optionalaccessories are available from your Authorized Raymarine
Dealer. Accessories may also be purchased directly from Raymarine
bycontactingtheCustomerServiceDepartmentat1-800-539-5539,
extension2333.
Description Part No.
Sidelooker transom-mount transducer M78930
Sidelooker transducer for trolling motor
(all-in-one unit senses depth below boat,
with Sidelooker and temperature sensor,
including mounting hardware) M78929
Extension for transducer cable (15 ft, 5 m) M99-140
Extension for transducer cable,
for Sidelooker transducer (15 ft, 5 m) M99-139

Chapter1:Introduction 3
Flush-mounting kit (with hardware and
mounting template) M92708
Fairing block for M78923 thru-hull
transducer (Lexan®) M99-142
Low profile plastic thru-hull transducer
(Valox®plastic, sensor for depth only) M78922
Bronze thru-hull transducer
(sensor for depth only) M78921
In-hull/trolling motor transducer (for installation in
fiberglass hull only, or mounting on trolling motor,
including hardware for either installation) M78928
Angled in-hull transducer (for installation
in fiberglass hull only, where deadrise
angle is 10°to 22°) M78946
Plastic thru-hull transducer (Valox®plastic, with
speed and temperature sensors, used with depth-
only transducers M78922, M78928, M78946) M78937
Transom-mount speed and temperature
sensor (used with depth-only transducers
M78922, M78928, M78946) M78936
Replacement transom transducer
mounting bracket kit M99-148
Transducer switch box (select between two L750
Fishfinder displays, using one transducer) M99-136
Replacement paddle wheel kit (for transom-
mount transducer) M99-143
Replacement paddle wheel kit
(for thru-hull transducer) M99-144
Note: Refer to page 75 for a list of repair parts.

L750Fishfinder:InstallationandOperationHandbook
4
Chapter2:Installation
Theinstallationprocesshasfour parts:
•Mountingthe transducer
•Mountingthedisplayunit
•Connectingthecablesforthetransducerand power supply
•Calibratingthedisplayunit
AbouttheTransducer
Severaldifferentkindsoftransducerscanbe used with this unit. The
“thru-hull”and “transom-mount”types areused mostoften. Other types
areshowninFig.2-1.
Fig.2-1 TransducerTypes
Mosttransducertypes can measurethe water depth. Someofthe
transducersalsohavetwoothersensors:apaddlewheelwhichdetects
thespeedof the boat,and a sensorfor the watertemperature. The
displayunitusesthespeedinformationtocalculate the distance the boat
hastraveled.
Thetransduceris very important totheoperation of theFishfinder. Itis
alsoimportant that youmount the transducercorrectly. The transducer
Thru-hull
transducer Fairing for
thru-hull transducer Transom-mount
transducer
In-hull
transducer Sidelooker
transducer
Low profile
transducer

Chapter2:Installation 5
willgivethemostreliablereadingsifitlooksintowaterwhichissmooth
andundisturbed. Ifyouplacethe transducer so bubblesorturbulence
flowacrosstheface of theunit,the system may giveinaccurate
readings.
Therearethree important rulesfor placing anytypeof transducer:
•Thetransducershouldbecontinuouslycoveredbywaterwhenthe
boatismoving. (If the transducerismounted near the sideof the
boat,itmaybeexposed when theboatisturning.)
•Thetransducershouldbeplacedwhereturbulenceorbubbleswillnot
passdirectlyovertheface of theunit. Don’tplace thetransducer
behindanyrunningstrakes,intakes,or thru-hull fittings which create
turbulence.
•Thetransducershouldbemountedwhere it will not beaffectedbythe
washfrom the propeller(s).
Selectingthe CorrectTypeofTransducer
Beforeyoubegintheinstallation,double-checktobesureyouhavethe
correcttypeoftransducer. Each kind of transducerisdesigned for a
particulartypeofuse. Inthismanualwewillincludedetailedmounting
instructionsforthe thru-hull andtransom-mount transducers. We will
alsoincludesomegeneralinformation on the other types. Fordetailed
informationonthese other transducers, seetheinstructions which are
packagedwiththeunit.
Usea thru-hull transducerif –
...your boat hasastraight-shaftinboard engine. This typeof
transducerisinstalledinaholedrilledthroughthehull.
Usea transom-mount transducerif –
...your boat has anoutboardorinboard-outboard engine(s) only. This
typeoftransducer must bemounted ahead of orbeside the propeller(s).
Donotusethis type of transducerfora boat with astraight-shaftinboard
engine.
Usean in-hull transducerif –
...you have ahigh-speedboator if, forsomereason,you cannot usea
transom-mountor thru-hull transducer.The hull maybe no morethan 1"
thick.

L750Fishfinder:InstallationandOperationHandbook
6
Usea trollingmotortransducer if–
... you wantto attach thetransducerto a trollingmotor.
Usea Sidelooker transducer if –
...youneed a way ofsearchingforfishon either side oftheboat. This
typeof transducer isattached tothe bracket ofthe transom-mount
transducer.
InstallingaThru-HullTransducer
Thisunitmaybeusedwitha thru-hull transducer. Please read this
sectioncompletelybeforestartingthe installation. Normally, thistypeof
installationisperformedbyaprofessional.
Fig.2-2 Thru-HullTransducer
2.00" dia.
(51 mm)
1.05"
(27 mm)
3.13" dia.
(79 mm)
5.24"
(133 mm)
5.50"
(140 mm)

Chapter2:Installation 7
BeforeYou Begin the Installation
Followtheseinstructionsif you areinstallingthe thru-hull transducer.
Hereare some rules to remember:
•Donotinstallthethru-hulltransducer, then leave yourboatinthe
waterforany amount of timewithoutchecking for leaks.
•Thepositionofthetransducerisespeciallycriticalonhighspeed
vessels(capableofmorethan 20 knots). Checkthelocationsofthe
transducersonsimilarboatsbefore installing thetransduceronyour
ownboat. Choosethelocationwhichwilloffer the best performance.
•Ifthehullofyourvesselhasacore-typehull,youwillneedtofollow
somespecialmountingprocedures. (If the core materialisallowedto
remainwet,itmayrot and weaken thehull.) Ifyouare in any doubt
aboutthiskindofinstallation, consult your boatrepresentativeoryour
Raymarinedealer.
Asetofinstallationinstructionswillbepackagedwitheachtransducer.
Thesewillgiveyoumoredetailedinformationthanwecanincludehere.
Thenotesinthissection will help youthroughthemostimportant parts of
theinstallationprocess. (Ifthe instructions in thepackagearedifferent
fromthenotesin this manual, followthepackagedinstructions.)
Selecting the Best Location for theTransducer
Followtheseinstructionsif you areinstallingthe thru-hull transducer.
Hereare some importantrules formounting the transducer:
•Forplaninghulls–Installintheflatplaningareanear the stern.
Alwaysinstallforwardofthe propeller(s) andshaft(s).
•Forsmalldisplacementhulls–Installnearthecenterlineofthehull
and1/3ofthe way forward fromthestern. Alwaysinstall forward of
thepropeller(s) and shaft(s).
•Forlargedisplacementhulls–Installnearthecenterlineofthehull
and1/3oftheway aft fromthebow. Alwaysinstallforward of the
propeller(s)and shaft(s).
•Forsailboats–Installforwardoftheleading edge of the keel,toone
sideandnearthecenterlineofthehull.
•Placetheunitwherebubbleswillnotpassoverthefrontofthe
transducer(especiallyathigherspeeds). Avoidanybubblescaused
byshaftstruts,fittings, or othertransducerswith paddle wheels. If you
noticeanyerosionofthepaintonthehull, this is a signofturbulenceor
bubbles.

L750Fishfinder:InstallationandOperationHandbook
8
•Choosealocationwherethetransducerwillalwaysbecoveredby
water.
•Thebeamfromthe transducer should notbeblockedby a keel or
prop shaft.
•Choosealocationwhereyoucaneasilyreach the transducer from
insidethevessel. Thiswillallowyoutomakeadjustmentsand
periodicinspections. Allowatleast6" (152 mm) ofheadroomabove
the transducer.
•The“deadrise”is the angle orslopeofthebottom of the hull inthe
side-to-sidedirection. Trytofindamountinglocation with the smallest
deadriseangle.
Fig.2-3 BestTransducerLocations
Mounting the Fairing Block
Followtheseinstructionsif you areinstallingthe thru-hull transducer.
Thetransducershould aim straight down(within 10°). Ifthebottomof
thehullisslopedmorethanthis, a fairing block maybenecessaryto
Sailboats
Best locations for
thru hull
transducers
Tri-hulls
Planing hulls

Chapter2:Installation 9
Inner part
of fairing
block
Outer part
of fairing
block
Lower part of
transducer
(front view)
Section
of hull
Upper part of
transducer
keepthetransducerperpendiculartothewaterline. Afairingblockwhich
canadjustforanglesofup to 25°is availablefromRaymarine.
1. Measurethedeadriseangleof the hull attheselectedmounting
point.
2. Cuttheblocktoashapewhich fits the exact contourofthehull. The
cut-outportioncanbemountedinsidethehullto provide additional
supportforthe transducer onceit is mounted.
3. Attachthefairingblocktothehullasfirmlyaspossible. Thisfairing
blockmustbeableto resist the dragofthewateragainst the hull, and
mustalsobe completely waterproof.
Fig.2-4 Installing a Fairing Block

L750Fishfinder:InstallationandOperationHandbook
10
Installing aThru-HullTransducer
Followtheseinstructionsifyouareinstallingthethru-hulltransducer.
Onceyouhavedecidedwheretoinstall the transducer, drill theholefor
the part.
1. Beginbydrillingasmallpilot hole (1/8" or3mm)fromthe inside of
thehull. (Thissmallholecanbefilledeasilyifthemountinglocation
isnotsuitable.) Beforeyoudrillthehole,besureyouwillbeableto
reachthelargenut on thetopof the transducer, onceithas been
mounted. Alsobesuretherewillbeenoughclearance for the cable.
Ifthereis a strake orotherfeature on thehull,drill from the outsideof
thehullinstead.
2. Drillalargerholefrom the outside ofthehullusinga 2" (50 mm)hole
saworpaddlebit.
3. Uncoil thetransducercable. Removethe large hexnutfromthe
housingandslideitovertheendofthecable.
4. Thread thecablethroughtheholetotheinsideofthehull. Never pull
orcarrythe transducer using thetransducer cable. This may break
thewiringconnectionsinsidethecable. Neverholdthetransducerin
placebypullingonthetransducercable.
5. Applyathin layer ofsealant(1/8" or 3mm)to the transducer
betweentheupperflat surface ofthetransducerand the fairing
block. Useahigh-qualitymarinesealantsuitableforunderwater
use. Alsoapplyathinlayerupthesidewalls. Thisshouldcoverallof
thethreadswherethepartwilltouchthehull material, plus an
additional1/4"(6mm). Thiswillseal the threads forthelargehex
nut.
6. Pushthetransducerhousing(withthesealantapplied)intothehole
fromtheoutsideofthehull. Twistthe housing slightly to squeezeout
anyexcesssealantandtoget a good seal. Be surethatthe
transducerisalignedso that thecorrectpartof the unitistowardthe
bowofthevessel. SeeFig.2-5. Holdor prop the transducer inplace
temporarily.
7. Gototheinsideofthe hull and slidethehexnutoverthe end of the
cable. Fitthehexnut over the endofthetransducer and tightenit.
(Onavesselwithawoodenhull, do not tighten thenutcompletely
rightaway. Allowsometimeforthewoodto swell after the vessel is
putinthe water.
8. Removeanyexcesssealant from the outsideofthe unit to assure
smoothwater flow overthe transducer.

Chapter2:Installation 11
9. As soonastheboatisplacedinthe water, check for leaks. Check
againwithin3to5hours. (Youmaynot be able to seeasmallleak
rightaway.) Ifthereare any leaks,youmustrepeat the installation
procedure.
Fig.2-5 Mountingthe Transducer Correctly
Assembling theTransducer Bracket
Followtheseinstructions if youareinstalling thetransom-mount
transducer.
Fittogetherthetwo parts ofthetransducer bracket as showninFig. 2-6.
Whentheinstallationis complete, the partssnaptogetheras shown.
Fig.2-6 AssemblingtheTransducer Bracket
This end forward
Paddle wheel
assembly near
rear.
Lower the transducer
and snap in the
release clip
Attach the
two parts Bracket is installed upside down
NOTTHIS!LIKETHIS!