Our top tips for maintaining a boat’s engine

A comprehensive boat maintenance programme will help to preserve the look, performance, integrity and value of your vessel. Whether it is the gunwhale or the bimini (yes, you might need to read our beginner’s guide to boat terminology), take the time to ensure all parts of your vessel are frequently cleaned, checked and serviced – especially when it comes to engine maintenance.

In a previous blog, we spoke in-depth about what regular maintenance should be done on a boat. We covered cleaning tips for various materials, storing your vessel, and saltwater boat maintenance, as well as providing a useful boat maintenance checklist. You can read our top maintenance tips blog here. Within the article, we did address engine maintenance, but such is its importance, we felt it was worthy of its own dedicated blog.

Table of Contents

— Do boat engines require regular maintenance
— Wear and tear on a boat engine
— Winterising a boat’s engine

Do boat engines require regular maintenance?

Whether you own a car, a boat, or even a lawnmower, the engine will always require some sort of maintenance – and a boat is no different. Whether you have an inland boat (where the engine operates at lower revs) or an offshore vessel (where the engine runs at a higher RPM for extended periods of time), upkeep is essential.

First and foremost, we always recommend that our customers carefully read the boat engine’s manual, which should clearly detail procedures required, plus a maintenance schedule.

All boat engines require an annual service, which should take place before it is stored for the winter period. Inboard engines can be serviced afloat, whilst outboards and outdrives need to be taken out of the water ahead of any service. A typical service should include changing the oil, plus both the oil and fuel filters. In addition, the plugs, impeller and fan belt will need replacing periodically, whilst the shaft seals should be checked, and the bilges should be cleaned.

Whilst we expect boat owners to use the professionals to carry out the more technical engine maintenance tasks, we do advise that they conduct regular engine checks themselves. This should involve:

• checking the wiring and pipework for any loose connections
• inspecting the condition and tension of the drive belt
• checking oil and coolant levels, like you would on a motor vehicle before going on a long journey
• listening to the engine for any irregular sounds
• looking in the bilges for signs of fuel, oil, or water leaks. Keeping the bilges clean will help with this
• using your sense of smell to check for any petrol leaks
• monitoring the levels of smoke coming out of the boat
• checking the indirect cooling filter and whether water is being pumped out of the exhaust
• checking the coolant level in the heat exchanger

Wear and tear on a boat engine

 Whilst out of the water, have a professional examine the anodes. Under hull equipment is covered by anodes, including outboard or stern drive, where the anodes are situated at the bottom of the leg.

Anodes act as small shields that protect the metal from deteriorating. If they are worn by at least a third, they will need replacing. In addition, look closely at the outer edges of propeller blades, as well as the cutless bearing for any cracks or general wear and tear.

There are three types of anodes – for use in salt water, brackish and fresh water. However, most boats that are used inland are made of fibreglass, and therefore anodes are not required.

Winterising a boat’s engine

Again, the process of winterising an engine should be outlined in the manual. We recommend running the inboard engine to warm the oil before changing the oil and filters.

You will also want to use a suitable antifreeze to protect your engine. With indirect cooling, run the engine and continue to poor mixed antifreeze into the weed filter until it comes out of the exhaust.

It is important to make sure that that inlet seacock is turned off if you’re afloat, and open if the boat is lifted. In addition, make sure to check whether the internal coolant antifreeze is of the correct strength. For outdrive direct cooled engines, the block will also need to be drained, however, outboards will drain themselves and there is no need to winterise.

Finally, you will need to:

• change the gear oil, check fluids, and change filters
• ensure cylinders are lubricate by run fogging agent in through the carburettor (outboards only)
• examine the stern drive, check oil, gaiters, locking pin, anodes and prop
• fill fuel tanks as a way of avoiding condensation (for diesel boats). If you have a small petrol tank, we advise you empty it and refill it in the spring. Larger petrol tanks can just be topped up with fresh petrol in the spring.

 From our marina in Wargrave, we offer a full complement of competitively priced standard and specialist boat maintenance services, working with an extensive range of highly professional engineers, mechanics, trimmers and finishers with the advantage of having a fully stocked chandlery on site. Get in touch via this form, or speak with one of our experts by calling 01189 403211.