Repair & maintenance guides

How to Replace the Water Pump Impeller

Replace the rubber impeller that pumps cooling water through your engine, the part most often behind overheating. On many outboards it is a two-hour driveway job that saves a shop bill of several hundred dollars and prevents far costlier heat damage.

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.

How to Service Sailboat Winches (Clean, Oil the Pawls, Grease the Gears)

Take your sheet and halyard winches apart, clean out old grease and salt, oil the pawls, lightly grease the gears and bearings, and put them back together. A serviced winch turns easily and, more importantly, its pawls catch every time so the drum can't spin backward under load.

How to Synchronize Twin Engines (RPM and Trim)

Twin engines running at slightly different RPM cause a pulsing drone, extra vibration, uneven wear and wasted fuel. Learn how to sync them by tach, sync gauge or ear, use the one-button sync on digital controls, check that your tachs tell the truth, match trim, and know when uneven engines or cable adjustment are a dealer job.

How to Test and Replace the Engine Thermostat

Find, test and replace the thermostat that controls your engine's operating temperature. A stuck thermostat can make an engine overheat or run too cold. On most outboards and many sterndrives it is a one-hour job with basic tools.

How to Use an Oil Extractor Pump for Boat Oil Changes

Change engine oil cleanly through the dipstick tube with a manual or electric extractor: know which engines it suits, warm the oil first, get as much out as you can, then refill to the dipstick, recycle the old oil and clean the pump so it's ready next time.

Ignition Tune-Up on an Older Sterndrive or Inboard V6/V8

Older carbureted sterndrive and inboard V6 and V8 engines need regular spark plugs, plug wires, distributor caps and rotors to start easily and run smoothly. Learn the signs a tune-up is due, how to replace these parts one at a time, why only marine ignition-protected parts belong in a gas engine bay, and why ignition timing is a job for a shop.

Marine Diesel Service: Oil Change, Fuel Filters and Bleeding Air

Change the oil and oil filter, replace the primary and secondary fuel filters, and bleed air from the fuel system on a Yanmar, Volvo Penta, Beta, Cummins or similar marine diesel. These three skills cover most routine diesel care and can get you out of trouble when the engine dies on a passage.

Marine Generator Routine Maintenance and CO Safety

Keep an Onan, Kohler/Rehlko, Northern Lights, Westerbeke or similar marine generator reliable with regular checks of oil, raw-water cooling, fuel, exhaust and the start battery, plus a monthly run under load. Generator exhaust is a leading source of carbon monoxide on boats, so safety checks come first.

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.

Salt and Scale in Raw-Water Cooling: Flushing Habits, Descaling and When It's a Shop Job

Learn how salt and scale slowly narrow your engine's cooling passages, how to spot the warning signs (a temperature that creeps up over seasons, a weak telltale, thermostats sticking), the flushing habits that prevent it, which descaling products and methods engine makers accept, what never to pour through an engine, and when to hand the job to a shop.

Testing Engine Coolant: Test Strips, Refractometer or Lab Analysis

Coolant can look perfect and still be worn out. Learn how to test the coolant in a closed-cooled inboard, sterndrive, diesel or generator with test strips, a refractometer or a mail-in lab kit, what each result tells you, and when the answer is a coolant change or a call to a mechanic.

V-Drive Transmission Care for Wake and Ski Boats: Fluid, Cooler, Coupler and Shaft Seal

Wake boats and many ski boats put the engine in the stern, backward, and turn the power through a V-drive transmission. Learn how to check and read the transmission fluid, why the cooler and its drain matter in winter, what the coupler and shaft seal tell you, and which noises and leaks mean it's time for a technician.