BoatMend

Repair & maintenance guides

Plain-English, step by step, written for owners. Pick your engine to see the guides that apply to it.

387 of 509 guides · page 4 of 17

TroubleshootingModerate

Engine Overheating - Troubleshooting Guide

Work through the most likely causes of a hot engine or overheat alarm, from a blocked water intake to a worn impeller or stuck thermostat. Acting fast and in the right order can save your engine and often gets you home without a tow.

1 h Outboard, Sterndrive (I/O), Gas inboard
Hull & systemsEasy

Engine Room Ventilation: Combustion Air, Blowers and Keeping Salt Out

Inboard engines, diesels above all, breathe huge amounts of air, and a hot or starved engine room quietly costs power, fuel and turbo life. Learn how engine-room air works, how to inspect vents, ducts, fans and salt-spray filters, the warning signs of too little air, and the separate gasoline blower rule.

1 h Marine diesel, Gas inboard, Sterndrive (I/O) Shop: $150-5000
TroubleshootingModerate

Engine Starts Then Dies - Troubleshooting Guide

Track down why your boat engine fires up and then stalls, whether at idle, when you shift into gear, or after a few minutes of running. Most causes are in the fuel supply and can be checked with no special tools.

1 h Outboard, Sterndrive (I/O), Gas inboard
TroubleshootingEasy

Engine Warning Horn and Dash Lights: What They Usually Mean and What to Do

Learn what a warning horn, beeps or a dash light usually mean on a boat engine, from overheating and low oil pressure to water in the fuel and reduced-power (limp) mode. Find out what to do right away and when to stop the engine. Patterns differ by brand, so match what you hear and see to your owner's manual.

30 min Outboard, Sterndrive (I/O), Gas inboard, Jet boat
TroubleshootingEasy

Engine Won't Start or Won't Crank - Troubleshooting Guide

Find out why your boat engine will not turn over or will not fire, starting with the simple things owners miss most, like the kill switch lanyard and battery switch. Many no-starts are fixed at the ramp in minutes without a tow.

45 min Outboard, Sterndrive (I/O), Gas inboard
SafetyEasy

EPIRB and PLB Care: Registration, Batteries, Self-Test and Mounting

Keep your 406 MHz emergency beacon ready to work on the worst day of your life. Register it free with NOAA and renew every two years, track the battery and hydrostatic release dates, run the self-test without triggering a false alert, and know what happens after you press the button.

30 min All engines
SafetyEasyDraft

Epoxy and Two-Part Paint Safety: How to Avoid Becoming Allergic

Epoxy and isocyanate-cured paints can make you allergic for life, sometimes after many jobs with no problem at all. Learn how sensitization happens, which gloves and clothing to wear, how to get epoxy off skin without solvents, when you need a respirator, and how to handle sanding dust and leftovers safely.

20 min All engines
Routine serviceEasy

Ethanol (E10) Fuel Care: Stabilizer, Phase Separation, Fuel Lines and Tank Vents

Keep E10 gasoline from damaging your boat engine. Learn how to use stabilizer, test for water and phase separation, and inspect the fuel lines, primer bulb, anti-siphon valve and tank vent. Most fuel-related breakdowns start with one of these.

1 h Outboard, Sterndrive (I/O), Gas inboard, Jet boat, Jet ski / PWC Shop: $100-300
Buying & ownershipEasy

Extended Warranties and Service Plans for Boat Engines: Factory Plans vs Third-Party Contracts

Decide whether an extended service plan is worth it: how factory plans such as Mercury Product Protection and Yamaha Y.E.S. differ from third-party contracts, what they usually cover and exclude, why maintenance records decide claims, how deductibles, transfers and cancellations work, and the questions to ask before you sign. Practical guidance, not legal or financial advice.

1 h Outboard, Sterndrive (I/O), Gas inboard, Marine diesel, Jet ski / PWC
Rules & seamanshipEasy

FCC Ship Station License vs. a Free MMSI: Which One Your Boat Needs, and How to Keep It Current

Most U.S. recreational boats that stay in U.S. waters don't need an FCC radio license, but every DSC radio and AIS needs a registered MMSI. Learn when an FCC ship station license and operator permit are required (foreign ports, SSB/HF, satellite), how to get an MMSI from BoatUS, America's Boating Club or Shine Micro, and what to do when you sell, buy or rename a boat.

45 min All engines
Buying & ownershipEasy

Financing a Boat: Loan Terms, Survey and Insurance Requirements, Liens and the True Cost of Ownership

Understand a boat loan before you sign: typical terms and down payments, what lenders check, why they want a survey and insurance, how the lien is recorded (Coast Guard preferred mortgage for documented boats, state title for the rest), how the payoff works when you sell, and how to add up the real yearly cost beyond the monthly payment. Practical guidance, not financial advice.

2 h All engines
Routine serviceEasyDraft

Fishing Line Behind the Prop: How It Ruins Gearcase Seals and How to Catch It Early

Fishing line that wraps behind your propeller can melt into a sharp ring that cuts the prop shaft seals and lets water into the gearcase. Learn the quick after-trip check, how to pull the prop and clear line safely, the signs that a seal is already damaged, and when to get a pressure test.

30 min Outboard, Sterndrive (I/O) Shop: $75-600
Hull & systemsModerate

Fixing a Sagging Cabin Headliner: Re-glue, Battens or Replace

Find out why cabin headliners sag, when a quick re-glue is worth trying, how wood battens make a lasting fix, and how to replace fabric, vinyl or panel liners safely with good ventilation and without drilling through the deck.

8 h All engines Shop: $500-3000
TroubleshootingModerate

Freshwater Pump Troubleshooting: Cycling, Won't Shut Off or No Water

When the pressure water pump keeps cycling at night, runs nonstop or sputters air, the cause is usually simple: an empty tank, a dripping fixture, a clogged strainer, air in the lines or a tired accumulator. Work from the cheapest checks to the pressure switch and pump, and learn the basics of replacing a pump.

1 h 30 min All engines Shop: $150-500
TroubleshootingModerate

Fuel Anti-Siphon Valve: Diagnosing a Sticking Valve and Replacing It Safely

The anti-siphon valve at your built-in fuel tank stops gasoline from draining into the bilge if a fuel line breaks, but a cheap or sticky one can starve the engine at speed. Learn how to tell a restricted valve from a blocked vent or filter, how to clean or replace it with a quality valve of the right type, and why you should never pull the check ball out.

1 h 30 min Outboard, Sterndrive (I/O), Gas inboard Shop: $150-400
TroubleshootingModerate

Fuel Demand Valves: Troubleshooting the Valve That Holds Back a Sealed Tank

Modern EPA-compliant fuel tanks stay sealed and build pressure in the sun, and a fuel demand valve keeps that pressure from pushing gasoline into the engine when it's off. Learn how it differs from an old-style ball anti-siphon valve, the symptoms of one that sticks closed or leaks through, how to rule out cheaper causes first, and why the replacement must be the same type, never a ball valve.

1 h 30 min Outboard, Sterndrive (I/O), Gas inboard Shop: $100-400
ElectricalModerate

Fuel Gauge Reads Wrong or Empty? How to Test the Gauge, Sender and Wiring

Find out why your boat's fuel gauge reads empty, full, backward or jumps around, working from the free checks at the dash to testing the tank sender and replacing it safely. Most problems are a stuck float, a bad ground or a sender that doesn't match the gauge.

1 h 30 min Outboard, Sterndrive (I/O), Gas inboard, Marine diesel Shop: $150-400
TroubleshootingModerate

Fuel Pump Checks - Is It the Pump or Something Starving It?

Bogging at speed, surging or dying after a few minutes is often blamed on the fuel pump, but vents, filters, primer bulbs and anti-siphon valves cause the same symptoms. Learn how mechanical, pulse and electric pumps work, the safe checks you can do, what the primer bulb is telling you, and why a real pressure test needs the right gauge and the factory spec.

1 h Outboard, Sterndrive (I/O), Gas inboard Shop: $100-500
SafetyModerate

Fuel Smell on Board: What to Do and How to Find the Source

A gasoline smell on a boat is a fire and explosion warning. Learn what to do in the first minutes, the most common sources (fill and vent hoses, tank fittings, fuel lines, carburetors and injectors, overfilling), how to look safely, and when to stop and call a pro.

1 h All engines Shop: $150-800
ElectricalModerate

Fuse Keeps Blowing? How to Troubleshoot a Boat Fuse Block or Breaker Panel

Work through a blown fuse or tripping breaker the safe way: confirm it, tell a short from an overload, isolate the device or wire at fault, replace a worn breaker or panel switch with the same rating, and label every circuit, without ever fitting a bigger fuse.

1 h 30 min All engines Shop: $150-500
SafetyEasy

Galley Stove Safety: Propane, Alcohol and Electric Cooktops Aboard

Cook aboard without fires or carbon monoxide scares by ventilating the galley, storing fuel the right way, checking flame-failure devices, using gimbals and pot holders, keeping an extinguisher and fire blanket in reach and never using the stove to heat the cabin.

45 min All engines Shop: $150-500
ElectricalEasy

Galvanic Isolator: Why Shore-Powered Boats Need One and How to Tell If It's Working

A galvanic isolator (or an isolation transformer on bigger boats) keeps stray DC current from the marina's ground wire from eating your anodes, drive and running gear, without cutting the safety ground. Learn what it does, the owner-level checks you can do, what failure looks like, and why the actual meter test is usually a job for a marine electrician.

30 min All engines Shop: $150-600
Routine serviceEasy

Generator Pre-Trip Check: What to Inspect and Test Before a Cruise

A marine generator that quits on the first hot night of a cruise usually gave warning signs at the dock. Use this pre-departure checklist, based on generator makers' own advice, to inspect the oil, coolant, belt, raw-water side, exhaust and CO alarms, run the set under real load, and pack the right spares.

1 h 15 min Marine diesel, Gas inboard, All engines Shop: $150-500
TrailerEasy

Get Your Boat Ready for the Road: Pre-Trailering Checklist

Most trailering trouble starts in the driveway: an engine left without support, a loose strap, a cover that balloons at 60 mph, gear that blows out or tongue weight that makes the rig sway. Work through this checklist before every trip and do a quick walkaround at each stop.

30 min All engines

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