Repair & maintenance guides

Boat Fuel Additives Explained: What Stabilizers, Ethanol Treatments and Boosters Really Do

The marine store shelf is full of bottles that promise to fix fuel problems. Learn what stabilizers, ethanol treatments, water removers, octane and cetane boosters, cleaners and diesel biocides actually do, what no additive can do, how to dose them by the label and why you should not stack several products in one tank.

Boating on High-Altitude Lakes: Power Loss, Prop Changes, Cold Water and Mountain Weather

Engines lose roughly 3% of their power for every 1,000 feet of elevation, so a boat that flew at sea level can struggle on a mountain lake. Learn what's normal, when a lower-pitch prop or a dealer adjustment helps, and how to handle the strong sun, cold water and fast-changing weather up high.

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.

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.

Gyro Stabilizer Care: Owner Checks for Seakeeper and Other Boat Gyros

A gyro stabilizer needs little from you, but what it needs matters. Learn how to start and shut it down correctly, keep its seawater cooling and zinc in shape, rinse it, read its hours and alarms, winterize it, and know which jobs belong to a certified dealer.

How to Break In a New or Rebuilt Boat Engine

The first hours on a new or rebuilt engine decide how well its piston rings seat and how long it lasts. Learn how to follow your maker's hour and RPM schedule, why you should keep changing the throttle, what to avoid (constant RPM, early full throttle, long idling), what to check every trip and when to do the first oil change.

How to Change the Oil and Filter on a Four-Stroke Jet Ski (PWC)

Pump the old oil out through the dipstick tube, swap the filter, refill and check the level the way your model requires. A yearly oil change (or at the hours your manual lists) is the single most important service for a four-stroke Sea-Doo, Yamaha WaveRunner or Kawasaki Jet Ski.

How to Find Your Engine's Serial Number, Model and Year (and Get the Official Manual)

Find the ID label on your outboard, sterndrive, inboard diesel or PWC, read the model and serial number correctly, tell it apart from the boat's HIN, and use it to open the free official owner's manual. It's the first step for ordering the right parts and following the right maintenance plan.

How to Inspect and Replace Spark Plugs

Pull, read and replace the spark plugs on a gas outboard, sterndrive, inboard or PWC. Fresh, correctly gapped plugs help the engine start easily and run smoothly, and the old plugs tell you a lot about the engine's health.

How to Keep a Boat Maintenance Log and Organize Your Receipts

Set up a simple maintenance log that records the date, engine hours, work done, parts and who did it, and keep receipts and photos organized. Good records help with warranty and insurance claims, show buyers the boat was cared for and reveal wear patterns before something fails.

How to Sea Trial Your Boat After Maintenance or Repair

A step-by-step test run after service work: dock checks first (leaks, fluids, steering, kill switch), then a gradual climb through the RPM range while you watch temperature and pressure, a wide-open-throttle check against your engine's spec, shifting and trim tests, and a bilge check afterward. Catch a loose clamp or a missed step at the dock, not miles out.

Jet Ski and Jet Boat Pump Care: Clearing the Intake Grate and Checking the Impeller and Wear Ring

Clear weeds, rope and rocks from the intake grate of a Sea-Doo, Yamaha WaveRunner, Kawasaki Jet Ski or jet boat, and learn to spot a damaged impeller or worn wear ring. A clogged or worn pump is the usual reason a jet craft revs high but goes slow.

Jet Ski Impeller and Wear Ring Replacement (What's Involved)

Know when your PWC's impeller or wear ring is worn out, how to check it yourself, and what replacing them really involves: pulling the pump, special tools, the right clearance, fresh seals and the correct pump lube. Most owners do the diagnosis and leave the pump work to a dealer or jet-pump shop.

Jet Ski Saltwater Care: Flushing, Rinsing, Corrosion Protection and Storage

A simple after-every-ride routine for Sea-Doo, Yamaha WaveRunner and Kawasaki Jet Ski owners who ride in salt or brackish water. Flush in the right order, rinse the pump, hull and engine bay the gentle way, spray anticorrosion only where it belongs, and keep anodes, the battery and the trailer from rotting away.

Moving Your Boat From Fresh to Salt Water (or Back): Anodes, Flushing, Corrosion, Bottom Paint and Trailer Upgrades

What to change when a lake boat moves to the coast, or a saltwater boat moves inland: switching anode material, a flush-after-every-trip routine, raw-water and closed cooling parts that wear faster in salt, bottom paint that suits your hull and drive, marine-grade hardware, and trailer upgrades that survive salt dunks. Built from BoatUS, Mercury, Yamaha and Boating Magazine advice.

Onboard Tool Kit and Spare Parts: What to Carry on a Day Boat or a Cruiser

Build a tool kit and spares box that fits your boat and how far you go. A blown fuse, a clogged fuel filter or a dinged prop shouldn't end the day or turn into an expensive tow.

Portable Toilets on Boats: Emptying, Chemicals, Odor, Seals and Winter Storage

A portable toilet (Porta Potti type) is the simplest legal head for a small boat, as long as it is emptied the right way. Learn where to dump it, which chemicals to use, how to stop odor and leaks, how to secure it aboard, and how to store it for winter.

Two-Stroke Oil Injection vs. Premix: How It Works and How to Check It

A two-stroke engine dies quickly without oil in its fuel, so the oil injection system and its alarms deserve regular attention. Learn how injection and premix differ, what the warning horn is telling you, how to check the system, how to premix safely using your manual's ratio, and the real risks of disabling injection.

Two-Stroke Premix Conversion: Living With an Engine That Had Its Oil Injection Removed

Bought a two-stroke outboard or PWC whose oil injection was removed, or thinking of doing it? Learn how to confirm what was done, mix fuel at the ratio from your manual every single time, label your tanks so nobody forgets, choose NMMA TC-W3 oil and understand the real risks.