PRACTICAL BOAT MECHANICS

Commonsense Ways to Prevent, Diagnose, and Repair Engine and Mechanical Problems

The McGraw-Hill Companies, Inc.

Contents

Excerpt

CHAPTER 1

THE NATURE OF THE BEAST

Before you begin caring for your boat's mechanical health and diagnosing andtreating its mechanical symptoms, you should meet the patient. Chapters 1through 9 offer a tour of your boat's mechanical mysteries and make a number ofsuggestions for routine maintenance. Caring for your boat's mechanical systemsis not only the best way to keep them functioning reliably, it's also the bestway to learn how they function and to prepare yourself for problem solving ifand when something does go wrong.

This chapter covers a few of the basics. Your boat may be brand-new, it maysimply be new to you, or it may be a mechanical mystery even though you've ownedit for several years. Whatever the reason, it's time to meet your boat and tofamiliarize yourself with a few of the techniques and circumstances you'llencounter again and again as you work with mechanical systems aboard.

THE BOATOWNER'S CHECKLIST

Before you use your boat, gather the information and make the inspections notedin this section. You need to be familiar with all the important systems on boardto properly maintain them and to know what to do if something goes wrong. You'llbe able to respond more quickly if you do your homework ahead of time.

1. Record the information from all engines and transmissions. Note: Thetransmission, which conveys engine power to the propeller shaft, is often calledthe marine gear, the gearbox, or simply the gear.

Every engine and transmission leaves the factory with a serial number plate(Fig. 1-1) to enable the ordering of parts and service work. Most often theseplates are attached with four small rivets. This same plate often provides theengine's power rating as well.

If no serial number plate is visible, begin looking for its original place onthe cylinder block. You'll know you've found it when you see a flat rectangulararea roughly two inches by three inches in size, framed either by four chiseled-off rivets or by the epoxy glue that once held the plate. When this is the case,you will have to get serial number information from the boat's previous owner.If this is not possible, an experienced marine mechanic can inspect theequipment and determine what was stamped on the plate.

If the plate is missing and there is no other way, it is worth hiring a mechanicto get you the information that was stamped on it. Don't be tempted to just letit go. You'll need the model and serial number whenever you call a mechanic forhelp. Your mechanic must have accurate information to know how your equipment isconfigured, especially if he or she hasn't worked on that type of engine ortransmission before. It's also vital information when ordering parts.

2. Determine if the boat's transmission has a come-home feature. If it does,know how to engage it. This information will be found in the transmissionservice manual. (See also Figure 14-3 and Chapter 6.)

3. Locate and clean the transmission oil suction screen and filter, if soequipped. Most hydraulic transmission clutch failures start with a pluggedsuction screen. A failure is easy to spot early by monitoring any accumulationof metallic debris in the suction screen.

4. Find and check the oil dipsticks for both the engine and the transmission.

5. Learn how to check the coolant level (Fig. 1-2), and in cold climates keeptrack of the level of protection provided by the antifreeze. The coolant shouldbe protected from freezing at temperatures as much as 20°F colder than theexpected local minimum temperature.

In addition, you should monitor the coolant conditioner, an additive thatminimizes the possibility of galvanic corrosion in the engine. You should dothis in warm and cold climates. Fuel supply docks and most auto parts storessell coolant test kits.

A large part of cooling system maintenance involves keeping the pH of thecoolant slightly alkaline instead of acidic. Acidic coolant acts as anelectrolyte, conducting corrosivecurrents between the dissimilar metals that exist in any engine's coolingsystem. Such currents, if unchecked, can cause galvanic corrosion that destroysmetal and any non-silicone rubber coolant hoses.

6. Check the engine's direct current (DC) electrical system, including thestarter motor, alternator, batteries, starter switch, the DC breaker or fusepanel, the engine and transmission gauges, all interconnecting wires, and oftenelectronic engine and transmission controls. Note: If your boat has an AC systemas well as DC, the two electrical panels are probably next to each other. Do notunder any circumstances poke around behind an AC panel unless you know withabsolute certainty that no power is flowing to the panel from a shore connectionor from an onboard generator set. If you have any doubts about your ability orthe system, call a marine electrician.

Write down the part numbers and operating voltages for the engine's startermotor and alternator. Also record the starter motor's direction of rotation(abbreviated on the starter motor plate as DOR or sometimes DIR), which willobviously be either clockwise (CW) or counterclockwise (CCW). Note: Alternatorsdon't care which way they turn.

Next, find the boat's battery selector switch or switches. There are twodifferent styles—the kind that can be switched with the engines running, and thekind that cannot. If your switch has two small wires running to it in additionto the battery cables, then it is the type of switch that can be operated (orturned) with the engine running. If there are no small wires running to theswitch, then it must not be turned with the engine running. Failure to observethis limitation will result in destroying the alternator. The boat may even haveboth kinds of switches.

7. After turning off any battery chargers (called constavolts in some parts ofthe U.S.) and all electrical loads, check the electrolyte levels in all liquid-electrolytebatteries with a good light. (This step does not apply to gel andabsorbed glass mat, AGM batteries, which are also generically called sealed orno-maintenance batteries.) If a battery's electrolyte is below the top of thebattery plates, add distilled water.

If the batteries are alike, with the same warranty date on each sticker, youhave found a sign of good maintenance. Dissimilar batteries should be replacedby a matched set when it is convenient.

8. After turning off all battery chargers and loads, disconnect, clean, andreconnect all battery terminals. Inspect all battery cables for crackedinsulation, which can result in short circuits or leak power to the electricalground and discharge the batteries over time.

Also, check the ends of the cables by lifting an edge of the insulation andlooking for green (copper) corrosion at the terminals. If corrosion is present,it may be a clue that the cable has been chronically wet or even submerged. Ifso, the cable must be replaced.

9. If your boat has a fire suppression system, find its sensors and controls andverify that the bottles are full. If you have any doubt about the system, have it inspectedby a fire and safety professional. If your boat has fire extinguishers ratherthan a suppression system, verify that the extinguishers are fully charged,properly inspected, and properly secured in their brackets.

10. Assuming the boat has a diesel engine or engines, locate all valves for bothsides of the fuel system (suction and the return). Note whether the fuel linesto and from the boat's fuel tanks are plumbed and valved to allow the engine orengines to pull fuel from the tanks on one side of the boat and send the returnfuel to the other side of the boat. This type of system is only found on largerboats. It is used to adjust trim as fuel in a port or starboard tank isdepleted. Note: If the fuel system is plumbed this way, then it is also possibleto return fuel to a full tank and thereby overfill the tank, sending fuel outthe tank's vent and causing a fuel spill. The Spill Guard by Herrington MarineTechnologies stops fuel spills by alerting the crew with a flashing light whenthe tank is full.

11. Verify that all external fuel tank fill openings are properly sealed. Ifthere is an O-ring seal on the fill cap, check it for visible damage and replaceit if needed. This will help keep water out of the fuel. Likewise, find the fueltank vents and be sure they are clear of obstructions.

12. Find the stuffing box (Fig. 1-4) and learn the best way to adjust it. Thestuffing box is where the boat's propeller shaft exits the hull. The stuffingbox contains the propeller shaft seal, and the job of the assembly is to keepthe ocean out of the boat while allowing the shaft to turn. Most stuffing boxesare designed to admit a slow drip of water, which lubricates the shaft, and thepurpose of adjustment is to obtain the proper drip rate. If the drip is toofast, the bilge fills with water; if it is not fast enough, the shaft overheats.Note: Newer boats are often equipped with so-called dripless propeller shaftseals.

13. Locate and check the condition of the boat's freshwater tank or tanks, andalso look for leaky or damaged hoses or fittings. The boat's freshwater systemshould include a replaceable activated charcoal filter with an exterior labelindicating the date it was last changed.

14. Find the best method for an emergency engine shutoff on your boat. SeeChapter 2 for more on this.

15. Locate the bilge pumps and bilge pump switches (Fig. 1-5), together withtheir fuses or breakers. Bilge pumps have two possible settings—manual orautomatic. Verify that each pump works properly on either setting.

16. Locate the engine cooling system's raw-water strainer and its valves, if soequipped. Check the freshwater (antifreeze) side of the system (Fig. 1-6) forevidence of leaks, damage to the plumbing, or chafing of these critical hoses.Replacing depleted sacrificial zincs is also important to prevent damaginggalvanic corrosion. Check the zincs and replace them as needed.

17. Locate all openings that pierce the hull and check for visible leaks, signsof corrosion (Fig. 1-7), and adequate tightness of the related fittings and hoseclamps.

18. Outboard engines: Check the engine mounting bolts for adequate tightness,fuel lines for kinks or chafing, and steering linkage for excess wear. Also,check all controls and electrical connections for anyapparent damage before starting the engine. If the engine is a newer four-strokeoutboard, remember that the intake and exhaust valves do need to be adjustedperiodically. If the engine is a two-stroke outboard, confirm whether it hasautomatic oil injection or not. If not, you will have to mix the oil into thefuel with each refueling. Read the engine manual to find the mixing ratio andthe type of oil to add to the gasoline. Stock plenty of two-stroke oil on theboat.

ENGINE START-UP PROCEDURES

The previous section showed you what to check on a boat you are just getting toknow. At the risk of some redundancy, here are procedures to follow each timeyou start your gasoline or diesel engine(s) to ensure long, trouble-freeservice:

* Check the engine and transmission oil levels.

* Check the coolant level.

* Remove the cover from a vertical

dry exhaust stack, if your boat is so equipped.

* Check the battery charge.

* Now crank and start the engine(s), keeping your eyes on the oil pressure gaugeto verify that the oil pressure is correct.

* Inspect the engine and transmission for leaks and excess noise.

* Idle the engine up to 1,000 rpm in neutral.

* Make note of the exhaust sound, and note the exhaust gas color; it must not bewhite.

* Unless your boat has a dry exhaust, make sure a healthy flow of cooling wateris coming out with the exhaust.

* When the water (coolant) temperature reaches 100°F, you can put the engine intogear and idle away from the dock.

* When the water (coolant) temperature reaches 180°F, you can throttle up theengine to cruising speed.

TOOLS AND EQUIPMENT TO HAVE ON BOARD

This section is not meant to list a complete inventory of the tools you mightneed aboard. The focus is on a few items that have repeatedly proven theirvalue. Here they are:

1. Jumper cables

2. A multimeter (electrical tester), along with the knowledge to use it (Fig. 1-9)

Note: NAPA auto parts stores sell an excellent booklet that explains how to testelectrical items with a multimeter. Strangely enough, it is titled Burn BabyBurn, and it explains why so many electrical components are needlessly replaceddue to ignorance of good electrical testing procedures.

3. LED flashlights

4. A shut-down paddle for stopping a runaway engine (see page 15)

5. Left-handed drill bits and Easy-Outs for removing broken bolts (see below)

6. A battery-powered Dremel tool (die grinder) and battery-powered carbide burrs(rotary files)

OTHER ITEMS TO HAVE ON BOARD

In addition to the foregoing, the following materials, spares, and fasteners maycome in handy. They are so easy to carry that it would be a shame not to haveany of them should the need arise.

1. You should have conversion charts to switch measurement units for bolt-tightening torque and for any other application.

2. Ultra-Gray Silicone Sealer is heat resistant and is especially useful becauseit sets up very firm. Good silicone sealants will replace many paper and fibergaskets.

3. Rolls of gasket paper in various grades and thicknesses are essential formaintenance and repairs. Both 1/32 and 1/16 inch are good thicknesses to have on theboat. In a pinch, however, a temporary gasket can be made from cereal box paper.Just cut open a Cheerios box and cut the gasket's shape from the paper, then puta light coat of silicone sealer on both sides and install. In addition, anypaper suitable for a gasket will also make a good shim.

4. Speaking of shims and shim stock, remember that some shims must be made ofmetal, such as steel, stainless steel, aluminum, brass, or copper. In a pinch,aluminum pop cans make a good shim. Galvanized and stainless steel stove pipeare also commonly available and make good shims.

5. Marvel Mystery Oil is an "upper cylinder lube," which means it is a goodlubricant for valve guides and piston rings. It is available at most fuel docksand auto parts stores and can be added to both the engine lubricating oil andthe fuel tank for use with either a gasoline or diesel engine.

6. It's important to carry both stainless steel and high-strength bolts andhardware on oceangoing boats. Engine bolts and fasteners, such as those thatmount the alternator, are high-strength. In the United States, a high-strengthbolt such as one of the ones attaching an alternator to an engine is called aGrade 8 bolt in the hardware and auto parts stores that sell them.

Spare fasteners come in ready-made kits from marine suppliers, or you can buy acase with many compartments and make your own selection. Other boaters will havegood suggestions based on their own experience.

7. Carry spare oil pressure and water temperature gauges and senders (Fig. 1-10).Engines have been rebuilt when all that was wrong was a failed oil pressuresender that showed no oil pressure. At the first sign of high water temperatureor low oil pressure, be sure to consider a failed sender. On the other hand, youshould definitely consider that the gauge is accurate until you know otherwise.Trust but verify; verify the alarming readings with mechanical gaugesthat provide a reading with no electrical input.

If you don't have mechanical gauges installed on the engine, consider carryingpressure and temperature test kits. These kits are available from Snap-on Tools.

8. Carry high-quality black and red electrical tape for insulation purposes andfor marking positive and negative electrical conductors.

9. You'll want to carry assorted sizes of crimp-on electrical terminals andheat-shrink tubing. The latter is plastic tubing that shrinks around electricalwires when heated. Small electrical supply kits are available at auto partsstores and offer a good assortment of terminals and heat-shrink tubing.

10. Aquarium-grade silicone sealant is handy to have for emergency repair of theboat's drinking water plumbing. If it won't harm fish, it won't harm you either!

11. Thread-locking compound (Loctite) keeps bolts and nuts from vibrating looseand is highly useful stuff to have around.

12. Spare engine-cooling system thermostats are important to have when an engineis running too hot or cold.

ROUTINE MAINTENANCE PROCEDURES

Know how to do the following routine procedures:

* crimp electrical terminals

* adjust your engine's valves

* adjust the fuel injection timing

* replace the water pump

* change the engine and transmission oil and filters

* change the engine air filter

* drain water from the fuel tanks

* switch from one fuel tank to the other while under way

EMERGENCY RESPONSE SCENARIOS

There are a few emergency topics you should consider at length well ahead oftime. If you do your homework regarding these potential problems, odds areyou'll never have to apply the knowledge. If you don't prepare for them, youknow how Murphy's Law works.

1. First, unless your diesel engine is self-bleeding, learn the procedure forbleeding air from its fuel system.

Note: All gasoline engines and some diesel engines have self-bleeding fuelsystems.

2. Learn the procedure for bleeding air from your engine's cooling system afterthe coolant has been drained and refilled.

3. Know all the possible sources of water that can sink or damage your boat, andknow how to halt each one.
(Continues...)Excerpted from PRACTICAL BOAT MECHANICS by BEN L. EVRIDGE. Copyright © 2009 by International Marine. Excerpted by permission of The McGraw-Hill Companies, Inc..
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