2001-2005 Mercury Mariner 25 HP Outboard Service & Repair Manual
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CONTENTS HOW TO USE THIS MANUAL 1·2 BOATING SAFETY 1-4 BOATING EQUIPME~ ( NOT REQUIRED BUT RECOMMENDED) 1010 SAFffi IN SERVICE 1·12 TROUBLESHOOTING , ·1 3 SHOP EQUIPMENT '·17 TOOLS 1-19 fASTENERS, MEASUREMENT , AND CONVERSIONS 1-27 SPECIFICATIONS '·28 GENERAL INFORMATION 2·2 LUBRICATION 2-4 ENGINE MAINTENANCE 2·9 BOAT MAINTENANCE 2·28 TUNE-UP 2-31 TIMING AND SYNCHRONIZATION 2-40 STORAGE 2·73 CLEARING A SUBMERGED MOTOR 2·n SPECIFICATIONS 2·79 FUEL AND COMBUSTION BASICS 3-2 FUEL TANK AND LINES 3·7 CARBURETED FUEL SYSTEM 3·12 ELECTRONIC FUEL INJECTION 3-44 OPTIMAX DIRECT FtlEl l NJECTJON ( OFI) 3-73 SPECIFICATIONS 3-107 UNDERSTANDING AND TAOUBLESHOOTING ELECTRICAL SYSTEMS 4-2 IGNITION SYSTEMS 4-8 CHARGING CIRCUIT 4-40 SPECIFICATIONS 4-43 ELECTRICAL SWITCHISOLENOIO SERVICE 4-64 WIAING DIAGRAMS 4-66 OIL I NJECTION SYSTEM 5-2 COOLING SYSTEM 5-11 WARNING SYSTEMS 5-31 COOLING SYSTEM FLOW SCHEMATICS 5-41 SPECIFICATIONS S-46
POWERHEAD MECHANICAL POWERHEAD RECONDITIONING POWERHEAO BREAK-IN SPECIFICATION CHARTS LOWER UNIT JET DRIVE MECHANICAL TILT (UNASSISTED) GAS ASSIST nlT SYSTEM POWER TllTfTRIM - SINGLE RAM INTEGRAL POWER nLT/1RIM· THREE RAM INTEGRAL REMOTE CONTROLS nllER HANDLE WIRING DIAGRAMS HAND ReWIND STARTER MASTER INDEX 6-2 6-57 .. 9 6-70 7-2 7-79 8-2 .. 8-10 8-2<1 9-2 9-7 9-14 1~2 1!H5 < CONTENTS MASTER INDEX
2·2 MAINTENANCE GENERAL INFORMATION (WHAT EVERYONE SHOULD KNOW ABOUT MAINTENANCE) At Seloc, we estimate that 75% of engine repair work can be directly or indirectly attributed to lack of proper care tor the engine. This is especially true 01 care during the off-season period. There is no w<fI on this green earth for a mechanical engine, particularly an outboard motor, 10 be left sitting idle for an extended period of time, say tor six months, and then be ready lor instant satisfactory service. Imagine, if you will, leaving your car or truck for six months, and then expecting to turn the key, having it roar to lile, and being able to dr ive off in the same manner as a daily occurrence. Theretore ij is critical tor an outboard engine to either be run (at least once a month), preferably, in the water and properly maintained between uses or for il to be specifically prepared for storage and serviced again immediately belora the start of the season . Only through a regular maintenance program can the owner expect to receive long l ife and satistactory performance at minimum cost. Many times, if an outboard is not performing properly, the owner will ' nurse" H through the season w ith good intentions of working on the unH once it is no longer bei ng used. As with many New Year' s resolutions, the good intentions are not completed and the outboard may lie for many months before the work is begun or the unH is taken to the marine shop for repair. Imagine, it you will , the cause of the problem being a blown head gasket And let us assume water has found its way into a cylinder. This water, allowed to remain over a long period of time , will do consklerably more damage than ~ would have if the unit had been disassembl ed and the repair work performed immedi ately. Therefore, if an outboard is not functioning properly, do not stow it away with promises to get at it when you get time, because the work and expense will only get worse the longer corrective action is postponed. In the example ot the blown head gasket, a relatively sillllie and inexpensive repair job could very well develop into major overhaul and rebuild work. Maintenance Equals Safety OK, perhaps no one thing that we do as boaters will protect us trom risks invol ved with enjoying the wind and the water on a powerboat But, each time we perform maint enance on our boat or mot or, we increase the likelihood that we will find a potential hazard before it becomes a pr obl em, Each time we inspect our boat and motor, we decrease the possibilrty that it could leave us stranded on the water. In this way, perlorming boat and engine service is one of the most important ways that we, as boat ers, can help protect ourselves, our boats, and the friends and family that we bring aboard. Outboards On Sail Boats (),yners of sailboats pride themselves in their abWty to use the wind to clear a harbor or for movement from Pori A to Port B, or maybe just for a day sail on a lake. For some, the outboard is carried only as a last resort· in case the wind fails completely, or in an emergency sHuation or tor ease of docking. Therefore, in some cases, the outboard is slowed below, usually in a very poorly ventilated area, and subjected to moisture and stale air· in short, an excellent environment for ' sweating' and corrosion. If the owner could just take the time at least once every month, to pull out the outboard, dean it up, and give it a shorl run, not only would he/she have 'peace of mind" knowlng it will start in an emergency, but aJso maintenance costs will be drastically reduced. Maintenance Coverage In This Manual At Seloc, we strongly feel that every boat owner should pay dose attention to this section. We also know that it is one of the most frequently used portions ot our manuals. The material in this section is di vided into sections to help simpl ify the process of maintenance. Be sure to read and thoroughly understand the various tasks that are necessary to keep your outboard in tip-top shape. TOpics covered in this secti on include: t. General Information (What Everyone Should Know About Maintenance) . an introduction to the benefits and need for proper maintenance. A guide to tasks that should be performed before and alter each use. 2. Lubrication Service· after the basic inspections that you should perform each Eme the motor is used, the most frequent form of perlodic maintenance you wi ll conduct wil l be the Lubrlcati on Service. This section takes you through each 01 the various steps you must take to keep corrosion fr om slowly destr oyi ng your motor before your very eyes. 3. Engine Maintenance· the various procedures that must be perlormed on a regular basis in order to keep the motor and all of its various systems operating properly. 4. Boat Maintenance· the various procedures that must be performed on a regular basis in or der to keep the boat hull and its accessories looking and working like new. 5. Tune·Up· also known as the pre·season tune-up, but donllet the name 1001 you. A complete tune·up is the best way to det ermine the condition of your outboard while also preparlng it for hours aoo hours 01 hopefully trouble·lree enjoyment And if you use your boat enough during a single season, a second or even third tune·up could be required. 6. Wint er Storage and Spring Commissioning Checklists· use Ihese sections to guide you through the various parts 01 boat and motor maint enance that protect your valued boat through periods of storage and return ~ to operaEng condi tion when ~ is time to use ~ agai n. 7. Specification Charts · located at the end of the section are quick· reference, easy to read charts that provide you wHh critical informaflon such as General Engine Specifications, Maintenance Intervals and Capaciti es. Engme (and Senal Number) Identificatton • See Figures 1 thru 5 For many years the engine serial numbers were Mercury's key to engine changes. These numbers identify the year of manufacture, the horsepower rating and the paris boo k ident~ication. If any correspondence or paris are required, it is still a good klea to use the engine serial number to make SURE you get the right part. However, we're happy to report that more and more Mercury has come in line with other engine manufacturers and is slicking doser and closer to model years than ever before. At l east one of the serial number tags used by Mercury on their newer 2·strokes i ncludes a specifiC spot which displays the MODEL YEAR of the mot or (along wHh the serial number, hp rating, weight rating, and year of manufactural . • Al so remember that the serial number tag estab lishes the model year and th e y'ear In which the engine was produced which is (or are) not necessarily the year of first installation. Two serial numbers tags were placed on each of these mot ors. One is attached to the powerhead itseH, usually on the lower starboard side of the powerhead, but on some 75 hp and larger motors ~ may be instead affixed to the TOP of the powerhead. All motors are also equipped with a serial number ID tag on the swivel bracket. For the smallest mot ors (2.5/3.3 hp models) this tag may be on the top center of the swivel bracket, but for most Mercury motors it is found on the starboard SIDE 01 the swivel bracket. F or mora information on engine identification and specifications, please refer to the General Engine Specifications charls later in this section. Before After Each Use As stat ed earlier. the best means of extending engine lile and helping to protect your self while on the water is to pay close attention to boaVergine maintenance. This starts with an inspection of syst ems and components before and after each time you use your boat. A list of checks, inspections or requi red maintenance can be found in the Maintenance Intervals Chart at the end of this section. Some of these inspectjons or t asks are performed before the boat is launched , some only after it is retrieved and the rest , both times .
VISUAllY I NSPECTI NG T HE BOAT AND MOTOR • See Figures 6 and 7 ~SY Both before each launch and immediately after each retrieval , vi sually inspect the boat and motor as follows : 1. Check the fuel and oil levels according to the procedures in this manual. 00 NOT launch a boat without properly topped off f uel and (i l applicable) oil tanks. 1\ is not worth the risk of getting stranded or at damage to the motor. Ukewlse, upon retrieval, check the oil and fuel levels while if is still fresh in your mind. This is a good way 10 track fuel consumption (one indica1ion 01 engine performance). For oil injected 2·stroke motors, compare the fuel consumption 10 the oil consumption (a dramatic change in proportional use may be an early sign of trouble). 2. Check lor signs of fuel or oil leakage. Probably as important as making sure enough f uel and oil is onboard, is the need to make sure that no dangerous conditions might arise due 10 leaks. Thoroughly check all hoses. littings and tanks for signs of leakage. Oil leaks may cause the boat to become stranded. or worse. could destroy the motor jf undetected for a significant amount of time. Fuel leaks can cause a fire hazard, or worse, an explosive condition. This check is not only about properly mai ntaining your boat and motor, but about hetping to protect your tife. MAINTENANCE 2-3 , CAUTION On fuellnjecled motors (ESPECIAllY EFI or Optlmax) fuel is pumped at high pr essure through various lines under the motor cowl. The smallest leak will allow for fuel to spray in a fine, atomized and highly combustible stream from the damaged hoselfilling. It is critical that you remove the cowling and tum the key 10 Ihe ON position ( 10 energize the fuel pump and begin building system pressure) for a quick check before starling the motor (to ensure that no leaks are present). Even so, leaks may not show until the molor is operating so II is a good idea to either leave the cover off untillhe molor Is running or 10 remove it again laler In the day to double-check thai you are leak tree. 01 course, if you DO remove the cover with the engine running take GREAT care 10 prevent contact with any moving paris. 3. Inspect the boat hull and engine cases for signs 01 corrosion or damage. Don't launch a damaged boat or motor. And don·t surprise yourseH dockside or at the launch ramp by discovering damage that went unnoticed last lime the boat was retrieved. Repair any hull or case damage now. 4. Check the battery connections to make sure they are clean a nd tight. A loose or corroded connection will cause charging problems (damaging the system or preventing charging). There's only one thing worse than a dead battery docks1deJIaunch ramp and thaI's a dead battery in the , • Top of $Wi ..... bracket 2 . port side ot cylind",. bIocl< Fig. 1 Serial number locations (1 = block, 2 = swivel bracket) - 2 .513 .3 hp outboards Fig. 2 A serial number tag is found on top of the swivel bracket for 2 .513 .3 hp outboards Flg. 3 Serial number locations (1 = swivel brackel, 2 = block) - 415 hp outboards , . SariaI Number 2· __ 3._~ 4· Y_ ManuT_o:rure<l 5· CenIti«I Europe lnsIgnio Flg.4 All 6-250 hp motors should have a serial number tag like this on the starboard side of the swivel bracket serial number lag found on Fig. 6 or fishing line entangled behind the II cut through the seal, water In or lubricant out
2-4 MAINTENANCE middle of a bay, river or worse, the ocean. Whenever possible , make a q uick visual check of battery electrolyte levels ( keeping an eye on the lavel will give some w arning of overcharging pr oblems). This is especi ally true ~ the engi ne is operated at high speeds for extended periods of time. 5. Check the propeller (Impeller on jet drives) and gearcase. Make sure the propeller shows no signs of damage. A broken or bent propeller may allow the engine to over·rev and it will certai nly waste fuel. The gearcase should be checked before and after each use lor si gns of leakage. Ch eck the gearcase oil for signs 01 ronlamination ff any l eak age is noted. Also, visually ch eck beh ind the propeller for signs of enlangled rope or fishi ng lines that could CUl1hrough the lower gearcase propeller shaft seal. This is a common cause 01 gearcase lubricanl l eakage, and eventually, w ater contaminati on that can lead to gearcase failure. Even ff no gearcase leakage is noted w hen the boat is first retrieved, check again next time betore launching . A n ick ed seal might not seep Huid right away when still swollen from heat i mmediately after u se , but might begin seeping over the next day, w eek or month as ij sal, coo'ed and dried out. 6. Check aU accessible fasteners for tightness. Make su re all easily accessi bie lasteners appear to be tight. This is especially true tor the propell er nut, any anode retaining bolts, all steering or th rott le li nkage lasteners and the engi ne cl amps or mounting bo~s. Don't risk loosing control or becoming stranded due to loose fasteners. Perform these checks before h eading out, and immediately after you return ( so you' ll know it anything needs to be serviced before you want to lau nch again .) 7. Check operation of all controts including the throtlle/shlf1er , steering and emergency stopfstar1 switch and/ or safety lanyard. Betore launching, make su re that all linkage and steeri ng components operate properly and move smoothly th rou gh their range of motion. AU electrical switches ( such as power trimtti lt) and especially the emergency stop system(s) must be in proper working order. While u nderway, walCh for signs that a syst em is not working or has become damaged. With the steering , shifter or throttle, keep a watchful eye out for a change in resistance or the start of jerkytnotchy movement. 8. Check the water pump intake grate and wat er Indicator. The water pump intake grate shou ld be clean and u rdamaged before selling out Remember that a damaged grate coul d allow debris i nto the system that cou ld destroy the impeller or dog coo l ing passages. Once underway, make sure the cooling indicator stream is visi bie at all limes. Make periodic ch ecks, includi ng one final check before the motor is shut down each time. If a cool ing indicat or stream is not present at any point, troubieshoot the problem before further engi ne operation. LUBRICATION About Lubrication • See Figure 8 An ou tboard motor's greatest enemy is corrosion. Face ij, oil and water just don1 mix and , as anyone who has visited a junk yard MOWS, metal and water aren't the greatest 01 friends either . To expose an engine to a h arsh marine env i ronment of w ater and wind is to expect that th ese elements will take their toll over time. But, there is a way to fight back and help prevent the natural process of corrosion that will destroy your beloved boat motor. Various marine grade lu bricants are available that serve two important functions in preserving your mot or . Lubricants reduce fr iction on metal-to- metal contact surlaces and. th ey al so displace air and moisture, therefore slowing or preventing corrosion damage. Periodic lubrication services are your best method of preserving an outboard motor. Marine lubricants are desi gned for the harsh environment to which outboards are exposed and are designed to stay in place, even when submerged in water (and we've got some bathing sui ts with marine grease stains to a tt est to this). Lubrication takes pl ace through various forms. For a ll engi nes. i nternal moving parts are l ubricated by engine oil, in the case of 2-stroke motors it is th rough oil contained in the fuell oil mixture. Also, on all conventional motors ( as opposed to jet drives) the gearcase is fiJled with gear oil that lubricates the driveshaft, propshaH, gears and other internal gearcase components. The gear oil should be peri odically checked and replaced lollowing the appropriate E ngi ne Maintenance procedures. Perlonn these services based on time or engine use, as outl i ned in the Maintenance Intervals chart at the end of this secti o n. Afwa ys make sure the transom plug Is installed and launch 9. If used In sail, brackish or poHuled walers Ihoroughly rinse the engine ( and huH), then flush the cooling system according to the procedure in this section. • Keep In mind that the cooling syslem can use al tenllon, even if used in fresh waters. Sand , silt or other deposits can help clog passages, chemicals or pollutants can speed corrosion . II's a good idea 10 flush your motor after every use, regardless of where you use it. 10. Visually Inspect all anodes after each use for signs of wear, damage or to make su re they just plain didn't f all off ( especiall y ~ you w eren't caref ul about checklng all the accessible fasteners the last time you launched). 11 . For Pete's sake, make sure the plug Is In! We shouldn't h ave to say it, but unfortunately we do. If you've been boating for any length of lime , you 've seen or heard of someone whose back ed a trailer down a launch ramp, forgetting to check the transom drain plug before submerging ( literally) the boat Always make sure the transom plug is installed ard ti ght before a lau nch. For motors equipped wi th pow er tri mltilt, the nuid levei and condition in the reservoir shoul d be check ed periodical ly to ensure proper operation. Pr oper fluid level not only ensures th at the system wi ll function properly, but also hel ps lubri cate and protect the internal system components from corrosion. Most oth er lonns 01 lubrication occur through the application of some fonn of marine grade ( usually either Qui cksi lver Anti-Corrosion Grease or Quicksilver 2·4-C wi th Tefl on ), either appli ed by hand (an old toothbrush can be helpful in preventing a mess) or using a grease gun to pump the lubricant into grease fittings (also known as zerlo; fittings). When using a grease gun , do not pump excessive amounts of grease into the f rtl ing. Unless otherwise directed, pump unlit either the rubber seal (i f used) begins to expand or until the grease just begins to seep from the joints of the romponent being lubricated (il no seal is used). To ensure your motor is getti ng the protection ~ needs, perfonn a visual inspection of the various lubricalion points at least o nce a week during regular seasonal operation ( this assumes that the motor is being used at least once a week). Follow the r ecommendations given and perlorm the various lubricating services at least every 60 days when the boat is operated in fresh water or every 3{) days when the boat is operated in salt, brack ish or polluted waters. We sa id at least meaning you should perform th ese services more often. H a need is di scovered by your weekly inspections. • J et drive models require ooe form of tubrlc al ion EVERY time thal they are used. The jet drive bearing shoutd be greased , followinglhe procedure jlV en In this section, after every day of boating. But don 't worry, it on y takes a minute once you've done it before.
Fig. 8 Mercury/Quic ksil ver products will do much to keep the outboard unit running right lubricating the Motor • See Figur es 9 thru 15 The first thing you should do upon purchasing a new or "new 10 you' molor is to remove the engine top cover and look for signs of grease, Nole all COfTllOllents that have been freshly greased (or if the motor has been neglected that shows signs of wear or dirVcontamination thai has collected on the remnants of okl applied grease). If the motor shows signs of dirt, corrosion or w ear, dean those components thoroughly and apply a Iresh coat of grease. Thereafter, lubricate those surfaces at LEAST every 60 days (more often if used in salt or corrosive environments) and grease all necessary surfaces regul arly to keep them clean and well lubricated. As a general rule of Ihurrb any point where two metallic mechanical parts connect and push , pul l, lum, slide, pivot on each other should be greased. For most motors this w ill incl u de shifl and throttle cables and/or linkage, steering and swiveling points and items such as the cowl damp bolts (on smaller motors) and top cover or cowling clamp levers. • For more information on greaslng and lubrication poI nts, check your owner"s manual. Most owner's manuals will provide one or more UluslraUons to help you properly ldenUfy all necessary greasing poInts. Points such as the swivel bracket and/or the tilt tube will normally be equipped with grease (zerk) littings. For these, use a grease gun to carelully pump small amounts of grease into the littings, displacing some of the older grease and lubricating the intemal surfaces of the swivel and ti~ tubes. Some engine cowl levers require a dab of lubricant be applied manually over sliding surfaces, but some may also equipped with grease fittings for lubrication using a grease gun. MAINTENANCE 2·5 · - CAUTION When lubricating the steering linkage grease fitting Ihe cable core must be completely retrac1ed Inlo the housing BEFORE applying the lubricant 10 the fitting. Failure to do this may cause hydraulic lock of the cable. Items without a grease fitting, such as the steering ram, cable ends, shifter and carburetor or throttle body li nkage all must normally be greased by hand using a small dab of lubricant. Be sure not to over apply grease as H is just going to get over everything and exposed grease will tend to attract and hold dirt or other particles of general crud. For this reason it is always a good idea to wipe aw ay the old grease before applying fresh lubricant to these surfaces. • The automatic belilensioner assembly on some motors, like the mid· range EFI models, may contain a zerk fitting for greasing. When present, it's usually pretty obvious, but check the assembly on fuel Injected models JUST to be sure. Lubrication InSide the Boat The following poi nts inside the boal will also usual ly benefit from lubrication with an all purpose marine grade lubricant: • Remote control cable ends n9}:t to the hand nut. DO NOT over- lubricate the cable. • Steering arm pivot socket. • Exposed shaft 01 the cable passing through the cable guide tUbe . • Steering link rod to steering cable. Lower Unit • See Figures 16 and 17 Regular maintenance and inspection of the lower unit is critical for proper operation and reliability . A lower unit can quickly fail if it becomes heavi ly contaminated with water or excessi vely Iow an oil. The most common cause of a lower uni t failure is w ater contaminati on . Water in the low er unit is usual ly caused by fishing line or other f oreign material, becoming ent angl ed around the propeller shah and damaging the seal. If the l ine is not removed , ~ wil l eventually cut the propeller shaft seal and allow water to enter the lower uni t. FIShi ng line has also been known 10 cut a groove in Ihe propel ler shah if left negl ected over time. This ar ea should be checked frequently. O IL RE COMM ENDA T IONS • See Figure 18 Use only Quicksilver Gear Lube or and equivalent high quality SAE 85·90 weight hypoid gear oil. These oi ls ale proprietary lubricants designed to ensure optimal performance and to minimize corrosion in the lower unit. • Remember, it is thi s lower unit lubricant Ihat prevents corrosion and lubricates the internal parts of the drive gears. Lack of lubrication due to water contamination or the Improper type of all can cause catastrophic lower unit failure. Fig . 9 Various lubrication points on the powemead should be maintained regularly to ensure a long service life including all rotallng . .. Fig. 10 ••• or sliding linkage points and cable ends
2-6 MAINTENANCE CHECKING GE A RCA SE OIL LEVEL & CONDI T ION • See Figures 19 and 20 ~SY Visually inspect the gearcase before and after each use tor signs of leakage. At least monthly, or as needed , remove the gearcase level plug in order to check the lubricant le vel and condition as follows: I. Position the engine in the upright position wi th the motor shut off for alleasl1 hour. Whenever possible, checking the level overnight cold will give a true indica~on 01 the level w ithout having to account f or heat expanSion. 2. Disconnect the negative banery cable or remove the propeller for safety. CAUTION 12 Steering cable grease fitting s and pivot poinllubricalion Always observe extreme care when working anywhere near the propeller. Take steps to ensure lhal no accIdental allempllo start the engine occurs whil e work Is being performed or remove the propeller completely to be sale. Fig. 13 grease II contains Fig. 16 This low er unit was destroyed because the bearing carrier froze due to lack 01 lubrication Fig. 17 Fishing line entangled behind the prop can actually cut through the seal
3. Position a small drain pan under the gearcase, toon unthread the drainlfiller plug al the bottom of the housing and allow a small sample (a teaspoon or l ess) to drain from the gear cast!. Quickly inSlalllhe drain/filler plug and tight en securely. 4. Examine the gear oil as fol lows: a. Visually check the oi l for obvious signs of water. A small amount 01 moisture may be present from condensation, especiall y if a motor has been stored for some ti me, but a milky appearance ind i cates that either the fluid has not been changed in ages or the gearcase allowing some water to intrude. If significant water contamination is present, the firs t suspect is the propeller shaft seal. b. Dip an otherwise cl ean finger into the oil, then rub a small amount 01 the fluid between your finger and your thumb to check for the presence of debris. The lubricant should feel smoot h. A very small amount 01 met allic shavirgs may be present, but should not really be f eM. large amounts of grit or met allic partides indi cate the need to overhaul the gearcase looking for damaged!wom gears, shafts, bearings or thrust surfaces. Fig. 19 Mercury often labels the oil vent/level plug (or plugs) on their Fig. -20 Typical oil ventilevel and drain plug locations on a Mercury gearcase MAINTENANCE 2-7 • If a large amount 01 lubricant escapes when the level/vent plug is remo v ed In the nen step, either the gearcase was seriously overfilled on the last servIce, the crankcase is slilltoo hot from runnI ng the molor in gear (and the lIuid is expanded) or a large amount 01 water has entered the gearcase. If the later is true, some water should escape before the 011 and/or the oil will be a milky white in appearance (showing the moisture contamination). 5. Next, remove the leveVvent plug Irom the lop of the gearcase and ensure the lubricanllevel is up to the bottom of the leveVvent plug opening. A very smal l amount of fluid may be aclded through the level plug, but l arger amounts of fluid should be added through the drainlfiller plug opening to make certain that the case is pr operly filled. If necessary, acid gear oil unt il fluld flows from the IeveVvent opening. If much more than 1 oz. (29 ml) is required to fill the gearcase , check the case carefully for leaks. InstaJl the drainlfiller plugs and/or the leveVvent plug , then tighten both securely. • One trick that makes adding gearcase oil less messy is to install the level / vent plug BEFORE removing the pump from the drainlfiller opening and threading the drainJfilier plug back into position. 6. Once fluid is pumped into the gearcase, let the un~ si t in a shaded area f or at least 1 hour lor t he lIuid to settle. Recheck the lIuid level and, il necessary, add more lubricant. 7. Install the propeller and/or connect the negative battery cable, as applicable. DRAINING AND FI L LING • See Figures 21 and 22 CAUTION The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize your exposure to used engine oil. Protec1ive gloves should be wom when changing the 011. Wash your hands and any other exposed skln areas as soon as possible after exposure to used engine oil. Soap and water or waterless hand cleaner should be used. 1. Place a suitable container under the lower un~. n is usua lly a good idea to place the outboard in the @ed pos~ion so the drain plug is at the lowest pos~ion on the gearcase, this will help ensure the oil drains fully. 2. Loosen the oilleveVvent plug ( or plugs if they are separate) on the lower unit. This step is important! II the oilleveVvent plug (s) cannot be loosened or removed, you cannot refill the gearcase w~h fluid and purge ~ of air. • Never remove the vent or filler plugs when the lower unit is hot. Expanded lubricant will be released through the hole. 3. Remove the drainlfill er plug from the lower end of the gear housing followed by the oillevelfvent plug(S). 4. Allow the lubricant to completely drain from the lower unit. 5. If applicabfe, check the magnet end of the drain screw lor metal particles. Some amount of metal Is considered nor mal wear is to be expected but ~ there are si gns of metal chips or excessive metal particl es, the gearcase needs to be disassembled and inspected. 6. Inspect the lubricant for the presence of a milky wMe substance, water or metallic particles. II any of these cond~ions are present, the lower un~ should be serviced i mmediately. 7. Place the outboard In the proper pos~ion for filling the lower un~ (straight up and down) . The lower unit should not list to either port or starboard and should be completely vertical. 8. Insen the lubricant tube into the oil drain hole at the bottom of the lower un~ and injed lubricant until the excess begins to come out the oil l evel hote. • The lubricant must be IUled from the bottom to prevent air from being trapped in the lower unit . Air displaces lubricant and can cause a lack of lubrication or a false lubricant level in the lower unit. 9. Oil should be squeezed in using a tube or with the larger quantities, by using a pump kit to fill the gearcase thr ough the drain p lug. • One Irick that makes adding gearcase 011 less messy is 10 install the level /Vent plug(S) BEFORE removing the pump from the drainlfiller opening and threading the drainlfiUer plug back into position.
2-8 MAINTENANCE 10. Using new gasketslwashels (~equipped) install the oil JeveV venl pl ug(sj first, then instalilhe oil fill plug. 11. Wipe the excess oil from the lower un it and inspect the unit for leaks. 12. Place the used lubricant in a suitable container for transportation to an authorized recycling facility. Jet Drtve Bearing • See Agure 23 Jet drive models requ i re special attention 10 ensure that the driveshaft bearing remains properly lubricated . Mercury recommends that you lubricate the jet drive bearing using a grease gun after EACH days use. However, at an absolute minimum, use the grease fitting every 10 hours (in fresh water) or 5 hours (in salt water). Also, after about every 30 hours of qleraflon, the dr ive bear ing grease must be replaced. Follow the appropriate procedure: RECOMMENDED LUBRICANT Use Quicksi l ver 2·4-C with Tellon or an equival ent water-resistant NlGI No . t lubricant. Flg. 21 Gear 011 is the drain F ig. 22 The lower unh is I the drain DAILY BEARING LU BRICATI ON • See FiQures 24 aoo 25 ~SY A grease fitting is located under a vent hose on the lower port side of the jet drive. Disconnect the hose from the fitting, then use a grease gun to apply enough grease to the fitt i ng to Just fill the vent hose. BaSically, grease is pumped into Ihe fming until the old grease just slarts to come out Irom the passages through Ihe hose coupling, then r econnect the hose to the fitting . • Do not atte mpt to Just grasp the vent hose and pull, as it iii a UglYt lit and when It does come off, you'll probably go Hying if you didn't prepare for it. The easier method of removing the vent hose from the litting is to deflect the hose to one side and snap it lree from lhe IiIUng. GREASE REPLACEMENT • See Figures 24, 25 and 26 ~SY A grease fitting is located under a vent hose on the loWE!( port side of the jet drive. This grease fitting is utilized at the end of each day's use to add fresh grease to the jet drive bearing. But, (!Very 30 hours andlor 30 days (depending on the amount of use): the grease should be completely replaced. This is very similar to lhe daily greasing, except that a lot more grease it used. Disconnect the hose from lhe fitting (by deflecting illo the side until ij snaps froo from the filting), Ih en use a grease gun to apply enough grease to the filting unti! grease exiting the assembly fi l ls the venl hose. Then, continue to pump grease into the fitting 10 torce out all of the old grease (you can tell this has been accomplished when fresh grease starts to come out of the vent instead ot old grease, which will be slightly darker due to minor contamination trom normal use). When nothing but fresh grease comes out of the vent the fresh grease has completely displaced the old grease and you are finished. Be sure 10 securely connect the vent hose 10 the filling. Each time this is performed, inspect the grease for signs of moisture conlamination or discoloration. A gradual increase in moisture conlent over a few servlces is a sign of seal w ear that is beginning to allow some seepage. Very dark or dirty grease may indicate a worn seal (inspect and/or replace the seal, as necessary to prevent severe engi ne damage should the seal fail completely) . • Keep in mind that some discoloration 01 the grease is expeC1ed when a new seal is broken-In. The discoloration shoul d go away gradually after one or two additional grease replacement services. Whenever the jet drive bearing grease is replaced, take a tew minutes to awly some of that same water-resistant marine grease to the pivot points of the jet linkage. -- - Fig. 23 Jet dri ve models require lubrication of the bearing after each day 01 use, sometimes they are equI pped with a Jabel on the housing to remind the owner
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2001-2005 Mercury Mariner 25 HP Outboard Service & Repair Manual