MerCruiser Marine Parts & Spares

MerCruiser Parts: 3.0, 4.3, 5.0 and 5.7 engines plus Alpha and Bravo drives

MerCruiser is the most widely used sterndrive in the world, and at Repuestos Marinos we keep more than 4,000 references to cover it: 3.0 L four-cylinder, 4.3 V6, 5.0 and 5.7 V8 engines, the larger 6.2 and 8.1 units and the diesels in the range, along with Alpha One Gen I and Gen II and Bravo One, Two and Three drives.

We supply genuine Quicksilver and Mercury parts alongside approved aftermarket equivalents from manufacturers such as Sierra, which meet OEM specification and have years of proven service in the industry.

MerCruiser parts categories

Our 58 MerCruiser sub-families, grouped by system:

Cooling and water pump

• Impellers MerCruiser (13)
• Alpha Water Pump Repair Kits MerCruiser (14)
• Bravo Water Pump Repair Parts MerCruiser (22)
• Water Circulation Pumps MerCruiser (19)
• Thermostats and Gaskets MerCruiser (20)
• Thermostat Bodies MerCruiser (17)
• Coolers MerCruiser (9)
• Engine Hoses MerCruiser (60)

Carburation, injection and fuel

• Carburetors MerCruiser (19)
• Carburettor Repair Parts MerCruiser (29)
• Electric Fuel Pumps MerCruiser (16)
• Mechanical Fuel Pumps MerCruiser (13)
• Fuel Injectors and Oil Seals MerCruiser (13)
• Injection Sensors MerCruiser (18)
• Diesel Filter Connectors MerCruiser (24)
• Fire Extinguishers MerCruiser (5)

Ignition and electrical system

• Distributors MerCruiser (9)
• Distributor Caps MerCruiser (14)
• Rotors MerCruiser (12)
• Ignition Coils and Modules MerCruiser (17)
• Spark Plug Cables MerCruiser (13)
• Ignition Kits MerCruiser (7)
• Starter Motors MerCruiser (19)
• Alternators & Regulators MerCruiser (15)
• Sensors MerCruiser (23)

Alpha and Bravo drives, transom and trim

• Transom & Steering Piston Parts MerCruiser (4)
• Bellows MerCruiser (16)
• Anodes MerCruiser (39)
• Motor Couplings MerCruiser (8)
• Tail Tools MerCruiser (28)
• Trim Motors & Components MerCruiser (10)

Exhaust, belts and engine block

• Manifolds and Elbows MerCruiser (4)
• Exhaust Manifold Gaskets MerCruiser (5)
• Engine Kits and Gaskets MerCruiser (1)
• V-belts MerCruiser (18)
• Serpentine Belts MerCruiser (16)
• Pulleys MerCruiser (11)
• Engine Mounts & Silentblocks MerCruiser (13)
• Turbochargers MerCruiser (3)

MerCruiser drives: Alpha versus Bravo

Alpha One. The classic drive, light and affordable, for engines up to around 300 hp. Gen I and Gen II differ in gear ratio, lower unit design and several water pump components, so you must know which one you have before ordering a water pump kit or a bellows set.

Bravo One, Two and Three. Tougher units built for higher power. The Bravo One runs a single high-performance propeller, the Bravo Two a large-diameter propeller for heavy boats, and the Bravo Three a counter-rotating twin-propeller system. On Bravo drives the water pump sits in the drive itself, with servicing that differs from the Alpha.

The transom assembly is where the most silent trouble builds up: the gimbal and exhaust bellows crack over the years and let water into the engine bay or the gimbal housing. Inspect them every two seasons at the very most.

Servicing a MerCruiser V6 and V8

Water pump impeller: every 2 years or 100-150 hours. On an Alpha it sits in the drive and the unit has to come off; on a Bravo the procedure is different. This is the service job that saves the most engines.

Oil and filter: every 100 hours or annually. Use a dedicated 25W-40 marine oil; never automotive oil.

Gearcase oil: annually. If it comes out milky, water is getting past the seals: stop there and fix it before going out again.

Anodes: check every season. A MerCruiser has anodes on the drive, on the anti-ventilation plate, on the transom and sometimes on the block. Check them all, not just the one you can see.

Gimbal and exhaust bellows: inspect annually, replace every 3-5 years. This is the most expensive and most avoidable failure on a MerCruiser.

Cooling circuit: on raw-water-cooled models, internal corrosion of the block and manifold is the main enemy. Check manifolds and exhaust elbows every 5 years in salt water: when they fail, water goes straight into the cylinders.

Ignition: spark plugs, leads, cap and rotor every 100-200 hours on distributor models.

Genuine, aftermarket and 24-48 h shipping

Every product page states whether the reference is genuine Quicksilver/Mercury or approved aftermarket, and which models and serial number ranges it fits. The serial numbers of the drive and the engine are the essential detail for getting it right: MerCruiser changes parts within the same model depending on the serial range.

Shipping in 24-48 h to mainland Spain and the Balearics, 3-5 days to the Canary Islands and the rest of the EU. Orders placed before 14:00 leave the same day. Returns within 14 calendar days, plus technical support by phone and WhatsApp.

Frequently asked questions about MerCruiser parts

Which MerCruiser models do you cover?

The 3.0 L four-cylinder, 4.3 V6, 5.0 and 5.7 V8 engines, the larger 6.2 and 8.1 units and the diesels in the range, along with Alpha One Gen I and Gen II and Bravo One, Two and Three drives. More than 4,000 references in total across 58 sub-families.

How do I know whether my drive is an Alpha Gen I or Gen II?

They differ in gear ratio, lower unit design and several water pump components. The definitive detail is the drive serial number. You must identify it correctly before ordering a water pump kit or a bellows set, because the parts are not interchangeable.

How often should the impeller on a MerCruiser be replaced?

Every 2 years or between 100 and 150 running hours. On Alpha drives the impeller sits inside the drive and the unit has to come off to reach it; on Bravo drives the procedure is different. This is the service job that prevents the most serious failures.

Why do the transom bellows need checking?

Because the gimbal and exhaust bellows crack over the years and let water into the engine bay or the gimbal housing. It is the most expensive and most avoidable failure on a MerCruiser. Inspect them every season and replace them every 3 to 5 years even if they look sound.

Why do MerCruiser exhaust manifolds corrode?

On raw-water-cooled models, sea water circulates through the block and the manifold and corrodes them from the inside over the years. When the manifold or the elbow perforates, water goes straight into the cylinders. It is worth checking them every 5 years if the boat runs in salt water.

What oil does a MerCruiser take?

A dedicated marine oil, typically 25W-40 grade, changed every 100 hours or annually along with the filter. Do not use automotive oil: marine engines run at high sustained loads and in damp conditions that car oils are not formulated for.