Engine Belts
Have You Checked Your Engine Belts Lately?
When was the last time you had a good look in your engine room to make sure everything was in order? One crucial item to include on your checklist is your engine belts. The last thing you want is your trip interrupted, finding yourself stranded or struggling back to shore on just one engine—if you’re lucky enough to have two. Engine belts are affordable and replacing them is one of the simplest ways to extend the life of your engine and its components. Ideally, belts should be replaced once a year, or whenever you service your engine along with the oil and fuel filters.
Why Belt Tension Matters
If a belt is too tight, it can wear out pulley bearings and the belt itself much quicker. On the other hand, a loose belt can reduce alternator output or even come off entirely, causing a knocking noise as it rubs against the belt guard. If you notice black dust on your belt guard or around the front of your engine, this could be a sign of a problem. Never ignore unusual noises on your vessel—always ensure your gauges and warning lights are functioning. If your overheat light comes on or your voltmeter shows no charge from your alternator, it’s likely a belt issue. Generally, your belt should deflect no more than 1/2 inch or 13 mm when you press it firmly with your finger or thumb for correct tension.
Be Prepared with Spares
It’s wise to keep a spare set of belts in your kit. You can’t always rely on a chandlery being open on a Saturday night or Sunday. Even your used belt can serve as a handy backup in a pinch.
Post-Replacement Checks
After installing new belts, check them more frequently at first. They might need an adjustment or retension after some initial use.
Don’t Forget Your Pulleys
Alongside your belts, it’s important to check your engine pulleys regularly. Their condition directly affects your belt’s health. Inspect them by sight and touch for anything other than a smooth surface. If you spot rust, corrosion, or any imperfections—like those shown in the photo above—service the pulleys promptly. This doesn’t always mean you need to replace them; sometimes they can be renovated without removal.