ORESU-61-78-004 C. 2 Outboard motor Marine recreation maintenance tips ClilCilflipygy~l Qggr@] g. t by PeterL. Hendricks Adapted,by permission,from 8asic Outboard engines Hawaii County Agent OtstboafdMotor Maintenance,published Most outboards,given proper care, by the Universityof Hawaii SeaGrant require little serviceother than periodic Universityof Hawaii CollegeProgram, August I977 UNIHI. maintenanceand adjustment.The SeaGrant CollegeProgram SEAGRANT-AB-774i3 !. individualengine owner can handle mostof the periodicmaintenance. This bulletin was written to aid the individual in basic outboard maintenance skills. Mostof theprocedures are possible withoutspecial tools. If youare in doubt aboutyour motor's service, consult a dealer or, in minor cases,the factory- authorizedowner's manual for your Power particular engine, head Power source Thepower source for all outboard motors is the internal combustion, reciprocatingengine seefigure I!. The basic differencein thesepower sourcesis the way in whichthe fuel mixtureis ignited.Most outboards have their fuel ignitedby anelectric spark Otto Cycle er pump Engine!,as opposed to heat-of- ck vent compressionignition DieselCycle!. In mostoutboards, one complete crankshaftrevolution completesthe aust column seriesof eventsnecessary to makethe enginerun. This is calleda ttco-stroke er pump cycle. In a two-strokecycle engine,five itation eventsmust take place in two strokesof thepiston, or in onerevolution of the e crankshaft.They are: I! intake fuel and air!, ! compression,! ignition, ! power,and ! exhaust.A compressedfuel chargeis fired each time the pistonreaches the top of the cylinde, andeach downward stroke is a powerstroke. In orderto accomplishthis, the initial pressureof theincoming fuel-air Lower mixturemust be raisedto a point ~ anat gnmewhathie'her than the lowest othervAe,a freshcharge of fuel could Figure] .~utetcay dfetotngof typicalinternal combustion, reciprocating outboard engine Otto Cycle!, Oregon State University ExtensionMarine Advisory Prograsn A Land Grant / Sea Grant Cooperative SG 43 September 1978 not be admitted and the enginewould Periodic servicing 5. Lubricateall greasefittuigs, using not ruii. This elevationof pressure Many of the troublesrelated to manufacturer's recornrnended requiresthe useof an air pump, or outboard motors will bc much easier to lubricant, compressor,of approxiinatclythe same repair if caughtbefore they do extensive 6. Check remote control box, cables, volumeas the cylinder itself. damage,Sometimes the lack of proper and wiring harness, Shift lever Coincidentallv, such an air pump is serviciiig is thc primary causeof failnre. shouldmove through full rangefrom available ivith a minin»mi of additional The following list of proceduresmay rcvcrse to forward, Throttle lever parts, cost,or fricti<>nallosses bv help in a regiilarprogram of preventive shouklmove smoothly from low idle utilizing thc opp<>siteside of the pist<>n maintenance for your outboard. to full open.Lubricate exposed and cylinder asthe' pump. Suchengines, Pr<ser<>ice checkout, Perhaps the boat movablelengths <>f control cables. called crankcase-scate»ged, are almost has been out of the water and the engine Adjust lever tensionon controlbox universallyused in the outboardmotor hasnot beenrun for a l<>ngperiod say, so levers operate smoothly yet industry, severalmonths. Here are a fcw simple remainwhere positioned when you In the crankcase-scavengedengine, preserviceprocedures: take vour hand oif. mostof the frictional partsrequiring 1. Rem<>ve,clean, inspect, and properly 7. Checksteering controls for smooth lubrication are located in the fuel intake gap sparkplugs. Replace dcfcctive movcmcnt without slack; lubricate svstcin.Lubrication is accomplishedby plugs, Usenew gaskets and tighten mechanical steeri<> g, mixingthe requiredainount of oil with theplugs to thc manufacturer's R. Lubricate all carburetor and the fuel, so that a small amount of oil, in recommendations, ! magnetolinkages with the form of a fine mist, is drawn i>>tothe 2. Removeoil level plug from gearcase manufacturer's recommended crankcasewith eachfuel charge, and checkfor properoil level, lubricant. It shouklbe pointedout that thc neiv oil brought into the crankcasecan do 3, Thoroughlycle'm aiul refinishengine 9, Adjust tensionon magneto;md/<>r little morethan supplementthe losses; surface,as necessary, Undercut>at bare generat<>rdrive belts. therefore,it is necessarythat thc metal with anndyzingprimer such as 10. Clean and coat hattcrv terminals frictional partsbe well lubricatedat the zincchromate!, thenpaint witli with grease. time theengine is started.Thc uscof too marine enamel. 11, Checkthermostat and water pump much oil in the fuel mixture results in 4. Checkbattery for full chargea»d operation,Engine, when in neutral, sparkplug fouling, excessive carbon clean terminals, Clean and inspect shouldpump warm sprayof iviitcr buildup,and poor performance, as well battery cables.Cover cable not inure tlian 160 F, or 71 C! asbeing wasteful. Too little oil results connectionswith greaseto prevent from hole in exhaust tower, in excessivewear and shorterengine life. corrosion, 12. Checkbreaker points' condition and 5. If possible,r<>n inotor in testtank timing. prior to installingon boat. Check 13, Checkcarburetor and ignition water pumpand thermostatoperation. synchronization. Inseroice checkoat, 14. Checkcarburetor adjustment. On 1. Drain and Rushgearcase. Refill to mostmodels, turn high speed correctlevel, usingmanufacturer's adjustmentslowly clockwiseuntil recommended lubricant. engineloses speed or dies,then counterclockwise about 1/8 turn! 2. Remove and clean fuel filter bowl. Replacefuel bowlelement. Always until enginereturns to highestspeed. usenew filter bowl gasket. Turn low speedadjustment slowly clockwiseuntil engineidles roughly 3. Cleanand regap spark plugs to or dies, then counterclockwiseuntil recommendedgap. Replaceworn, it returns to smooth idle. cracked,or burnt sparkplugs. Use new gasketsand tighten plugsto manufacturer'srecommendations. ! 4. Checkpropeller for correctpitch. Replaceif propelleris badly worn, chipped,or bent. Installation Propertransom height and engine tilt arecritical to goodperformance. If the motor is mountedtoo high abovethe water,the propeller will slip,churn, and cavitatewith little usefulpower. If mounted too close to the water, the motor will drag, kick up excessspray, andtend to submergein a followingsea. Wrongangle or tilt of themotor pushes the bow or stern down, slows the boat, and wastes fuel. Most installations are just rightwhen thc lower unit isvertical at full boat speed,but you will probably want to experimentfor best performance. Figure 2. Propellerdiameter, Propellers one of t<co cornmo» Propellerselection seeAm<re 2! is dimensions used fo describe generallyan easymatter for the outboard propellers. owner. If the motor is used on an averagerunabout, the standardpropeller is usually ado<In»to. For other th,m averageconditions, yon I'igure3, Propellerpitch, the secondcommon dimension used in maywant to < hangeto a diHercntpitch describing propellers. propelier,Pitch is thetheoretical distancethat the pr«pclierwould travel Pitch in a solid substance if it made one completerevnluti<m without slippage Ag<trc3!. Increasingthe pitchreduces rpm at full throttle,while reducing the pitchwill increaserpm at full throttle. If your boat is largeand slow,you may do betterwith a low-pitch propeller;if yourboat is light andfast, higher pitch will help. An importantpoint is to usea propellerthat allowsthe engineto spin withinrated speed range at full throttle. Spark plugs Regularspark plug service is importantbecause outboards are tough on plugs.Use exactly the recommended plugs,clean and adjust gaps regularly, keepoutside porcelain dry, andalways carrya spareset of plugs.Remember to usea goodgasket when replacing the Pitch = distance travelled plugs.The gasket not onlyprevents loss of compressionbut is alsoresponsible for in one revolution keepingthe plug electrode at design temperature. Saltwater care 4, Checkfrequently to be surethat no Motors that are used in saltwater aluminumparts are left unprotected. presentspecial problems and require Protectbare metal quickly with an meticulouscare. Aluminum alloys usesl anodizingprimer and marineenamel in outboardmotors are highly resistant topcoat, to corrosionby oxidatiou breakdownof 5. A smallself-sacrificing block of metal, causedby its combinationwith unpaintedcorrosion-susceptible metal oxygen! but very susceptibleto galvanic a "zinc" mounted near the part action electrical processof depositing to be protectedwill sometimesspare a atoms of one metal, in solution, im the valuablepart from corrosion.Zincs surface of a dflferent metal!. can bc mounted. on the flat cavitation Although oxidation cannot occur plate, after stripping the finishdosvn under water, it is very prcvalcntin to hare metal, with stainless stce! or humid environments, Aluminum parts hot-dippedgalvanized screws. Al areprotected from galvanizaticm hy surfaces around the block must be anodizing the processof coatingmetal protcctcdwith paint,XOTE: Consult with a hard shell of aluminum oxide!. a dealerbefore attempts'ng to install But this coveringis onlv protectiveif it such a derice. remains unbroken. Here are some tips for care of all motors used in saltwater: 1. After each use, tilt the motor out of the water and Hush out the entire motor with cool, fresh water. Flush for 1 to 2 minutes and do so within 1 to 2 hoursof use to preventsalt For further