Repair & maintenance guides

How to Bleed Air From a Marine Diesel Fuel System

A diesel that sucks air after a filter change, a fuel leak or running the tank dry may not start until the air is pushed out. Learn the order that works on most older mechanical diesels, why common-rail engines are different, how to protect the starter and exhaust while cranking, and the high-pressure fuel dangers you must respect.

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 Build a Damage-Control Kit: Plugs, Patches and a Plan for Leaks

Put together a labeled kit that can slow or stop water coming into your boat - softwood plugs tied at every through-hull, rescue tape, spare clamps, rubber and plywood patches, plastic sheeting, underwater sealant, a manual pump and the tools to reach a hidden leak - and practice with it so your crew knows where everything is.

How to Care for a Hydraulic Jack Plate (Fluid, Pump, Leaks, Grease and Height)

Keep a hydraulic jack plate (Bob's Machine Shop, T-H Marine Atlas, CMC, SeaStar style) lifting smoothly: check and top up the right fluid, keep the pump and relays dry, find leaks and slow drift, lubricate only the way your model calls for, set running height safely and prepare it for winter. Mounting and setback changes are dealer work.

How to Care for Boat Solar Panels, Connectors and the Charge Controller

A boat solar setup is quiet and almost maintenance-free, but salt, shade, loose connectors and a wrong battery setting quietly cut its output or hurt the batteries. Learn the cleaning, inspection and controller checks to do each season, and how to leave the system for winter.

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 Change Marine Transmission (Gearbox) Oil

Check, read and change the oil in the reverse gear behind your inboard diesel (ZF/Hurth, Kanzaki, Yanmar KM, Volvo Penta MS and similar). Learn what milky, burnt or gritty oil means, and why the oil cooler and its zinc matter.

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 the Cutless Bearing, Prop Shaft and Strut

Find out if new vibration or rumbling from the stern is a worn cutless bearing, a bent shaft, a loose strut or poor engine alignment, using simple checks you can do at the dock and at haul-out. Catching bearing wear early protects the shaft, the seal and the transmission.

How to Check, Adjust and Repack a Stuffing Box (and Care for a Dripless Shaft Seal)

Learn the right drip rate for a traditional packing gland, how to adjust it safely, when to repack it, and how to inspect and service a dripless shaft seal. The shaft seal is one of the few holes in an inboard boat that moves, and a neglected one can sink a boat at the dock.

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.