Repair & maintenance guides
Plain-English, step by step, written for owners. Pick your engine to see the guides that apply to it.
400 of 509 guides · page 6 of 17

How to Care for Your Anchor Locker and Keep the Chain Running Free
Empty, clean and drain the anchor locker, untwist and restow the rode so it runs out without jamming, tie the bitter end so it can be cut free in an emergency, and decide whether you really need a swivel. A tidy locker keeps the anchor ready when you need it fast.

How to Change Lower Unit (Gearcase) and Sterndrive Oil
Drain and refill the gear oil in your outboard lower unit or sterndrive, and learn to spot water intrusion before it destroys the gears. It is a 30-minute job that protects a gearcase costing thousands to replace.

How to Change the Oil and Filter on a 4-Stroke Outboard
Drain the old oil, swap the filter and refill with the right marine oil on your 4-stroke outboard. It is the most common service job, takes about an hour, and costs a fraction of the dealer price.

How to Check a Boat for Transom and Stringer Rot
Many older fiberglass boats have wood inside the transom, stringers and deck, and water that gets in slowly rots it. Learn the tap test, the flex test, how to read a moisture meter and the other warning signs, and why a rotten transom or stringer is a structural job for a pro, not a weekend patch.

How to Check and Adjust Boat Shift and Throttle Cables
Hard shifting, a lever that will not go fully into gear, or a gear that lands in a different spot every time usually point to the control cables. Learn how to find out whether the problem is the cable, the control box or the engine, how to adjust the cable ends, and when it is time to replace both cables.

How to Check and Care for Boat Trailer Surge Brakes
Understand how the hydraulic surge brakes on your boat trailer work, check the fluid, use the reverse lockout correctly and rinse salt out of them after every dunk. Simple habits that keep the brakes from seizing, dragging or failing when you need them.

How to Check and Change Coolant in a Closed Cooling System
Check, test and change the coolant in a freshwater-cooled (closed cooling) inboard, sterndrive or diesel, and learn the heat exchanger basics that keep it working. Old coolant quietly eats hoses, pumps and engine passages, and many boats go a decade without a change.

How to Check and Test a Gasoline Vapor (Fume) Detector
A gasoline vapor detector sniffs the bilge all the time and sounds an alarm long before fumes can explode. Learn how these detectors work, where the sensor belongs, how to test the system the way its maker says, what causes false alarms, what to do when it goes off, and why it never replaces the blower and your own sniff test.

How to Check and Top Up Power Trim and Tilt Fluid
Check and top up the hydraulic fluid in your power trim and tilt unit, then work through the simple checks when the motor won't go up, won't go down or slowly sinks. Most trim problems are a dead battery, a bad relay, low fluid or a release valve left open, and you can find those yourself.

How to Check for Worn Outboard Motor Mounts
A clunk when you shift, buzzing vibration at idle or a motor that wobbles side to side can mean the rubber mounts between the outboard and its bracket are worn out. Learn how to rule out the cheap causes first, check the mounts yourself and know when replacement belongs in a shop.

How to Check, Mount and Replace Boat Fire Extinguishers
A monthly five-minute check of every fire extinguisher aboard, plus how the 2022 Coast Guard rule changes affect you, where to mount them, and when to recharge or replace. A boat fire spreads in seconds, and an extinguisher with a dead gauge, missing pin or expired date will not help you or pass a boarding.

How to Choose and Fit Life Jackets for Children and Babies
Pick the right Coast Guard-approved life jacket for each child by weight, check the fit so it can't slip off, look for head support and a crotch strap on little ones, and learn the federal and state wear rules. Inflatables are not for kids, and a life jacket never replaces an adult watching.

How to Choose the Right Outboard Shaft Length
Measure your transom, match it to a 15, 20, 25 or 30-inch shaft and check where the anti-ventilation plate ends up. The right length keeps the prop biting clean water and the cooling intakes fed; the wrong one means ventilation, overheating, drag or spray.

How to Choose, Install and Adjust Trailer Guide-Ons (Posts or Bunks)
Add or tune the side guides on your boat trailer so the hull lines up in wind and current, the posts stay visible at the ramp and nothing rubs the gelcoat on the road. Covers post vs. bunk guide-ons, lighted posts, mounting height, side clearance and yearly care.

How to Choose, Install and Maintain an Onboard Battery Charger
Pick the right marine charger for your batteries (how many banks, how many amps, flooded, AGM or lithium), mount and fuse it safely, set the charge profile, and use it to keep batteries healthy all season and through the winter. The AC (shore power) side is a job for a marine electrician.

How to Clean and Care for a Boat Windshield (Acrylic, Polycarbonate or Glass)
Clean your windshield without scratching it, tell acrylic, polycarbonate and glass apart, deal with haze, crazing and small cracks, stop frame leaks, and keep wipers and the walk-through door working.

How to Clean and Care for Clear Vinyl (Isinglass) and Polycarbonate Enclosure Panels
Keep the clear windows in your dodger, bimini curtains or full enclosure clear for years by cleaning them the right way, storing them without scratches and avoiding the cold-weather and chemical mistakes that ruin them. Covers soft clear vinyl, coated vinyl like Strataglass, rigid panels and zippers.

How to Clean and Protect Boat Canvas, Bimini Tops and Vinyl Seats
Wash your bimini, covers and enclosure the right way, beat mildew without wrecking the stitching, keep vinyl seats soft and stain-free, look after zippers and snaps, and store everything so it comes out clean next spring.

How to Clean the Carburetor on a Small or Older Outboard
Old fuel turns to varnish and plugs the tiny jets in a carburetor, so the engine only runs on choke, surges or will not idle. Learn when the carburetor really is the problem, how to drain and clean it, and when a rebuild kit or a replacement makes more sense.

How to Clean the Raw-Water Strainer and Replace the Impeller on a Marine Diesel
Clean the sea strainer and swap the rubber impeller in the raw-water pump of a Yanmar, Volvo Penta, Westerbeke, Beta or similar inboard diesel. A worn impeller is one of the most common reasons a diesel overheats, and this job takes about an hour with basic tools.

How to Clean Your Boat's Bilge (Legally, and Without the Smell)
Get oil, sludge and debris out of the bilge without pumping pollution overboard, choose absorbents that actually work, track down bilge odors, clear limber holes and the pump pickup, and dispose of the mess the right way.

How to Clean, Protect and Inspect Stainless Steel Boat Hardware
Remove tea stains and rust from rails, cleats and fittings without scratching them, passivate stainless so it stays clean longer, understand why 304 and 316 behave differently, and spot the hidden crevice corrosion that weakens fittings from underneath.

How to Clean, Protect and Restore Non-Skid Decks
Get dirt, fish blood, rust and mildew out of textured non-skid without wearing it away, learn why ordinary wax makes it dangerously slick, and decide when worn non-skid needs a deck paint with grip additive or traction pads instead.

How to Clean, Remove Oxidation and Wax Your Boat's Gelcoat (Plus Pontoon Tubes)
Wash your hull the right way, bring back chalky, faded gelcoat with compound, and seal it with wax so it stays glossy and protected from the sun. Includes how to clean and protect the aluminum tubes on a pontoon boat.
Safety: BoatMend is for information only and does not replace a certified marine technician. You are responsible for your safety and your boat. Read the full disclaimer.