MERCURY 893504T02 Outboard Powerhead Cylinder Head Ay 30/40HP

( Manufacturer Part Number: 893504T02 ), ( Part Type: Cylinder Head ), ( Country Of Origin: United States ), ( Please Open And Read Sellers Full Item Description: For Complete Product And Transaction Details. Thank You. ), ( Customer Service: 616 682-1560 ), ( Mfm Return Policy: For All Returns ), ( Regardless Of Reason : Buyer To Pay Return Shipping Costs And A 20 Return Fee ), ( From Outboard Serial No.: 0t086207 ), ( Model Group: 1f40412we 30 /40hp 4-stroke / Electric ), ( Includes Cylinder Valve Cover Bolts: Original, Stainless Steel Attachment Bolts ), ( Includes Cylinder Head Cover: Part No. 893693a04 ), ( Throttle Lever: 822682a2 ), ( Assembly Is Nla: No Longer Available, As No Longer Manufactured ), ( Complete Cylinder Head Assembly: Rockers, Cams, Intake And Exhaust Valves, Springs ), ( Various Mercury And Mariner Outboards: Including Some Big Foot Models ), ( Driven Gear: Part No. 833104t6 / T1 ), ( From Model No.: 40elpt 4s Elpt 4 ), ( Model Years: 1999-2006 ), ( Michigan Freshwater Marine: Customer Service ), ( Includes Fuel Pump: Part No. 826398t3 ), ( Shift Lever: 825957 1, From A Good-running ), ( Low Hour Outboard: 2000 40hp 3-cylinder 4-stroke Electric, Carbureted )

Review MERCURY 30/40hp Stroke Outboard Powerhead Cylinder Head Ay fits 1999–2005

The **Mercury 893504T02 30/40 HP Outboard Powerhead Cylinder Head** is a meticulously engineered component designed for the iconic **Mercury 30 and 40 horsepower outboard engines** produced between **1999 and 2005**, specifically tailored for the **AY series** (also known as the **400 series**). This high-performance cylinder head is a critical part of the engine s combustion system, responsible for housing the intake and exhaust valves, spark plug, and combustion chamber, all of which work in unison to deliver reliable power and efficiency. Crafted from **high-grade aluminum alloy**, this head is precision-machined to exacting tolerances to ensure optimal airflow, thermal management, and structural integrity under the demanding conditions of marine operation. The design incorporates **dual overhead valves (DOHC)** with **hydraulic valve lifters**, allowing for smooth operation and reducing wear over time, while the **integrated spark plug well** ensures proper ignition and combustion efficiency. This cylinder head is compatible with the **Mercury 30/40 HP outboard s carbureted or fuel-injected fuel delivery systems**, depending on the model year, and is engineered to withstand the stresses of saltwater corrosion, thermal cycling, and high RPM performance. Whether restoring a classic boat or upgrading an existing engine, this **OEM-quality replacement part** ensures peak performance, fuel economy, and longevity, making it an essential component for any serious boater seeking reliability and power. Built to meet Mercury s stringent manufacturing standards, this cylinder head is a testament to the brand s commitment to durability and performance, providing a seamless fit for engines in this popular displacement range.

### **Pros and Cons of Buying a Mercury 893504T02 (30/40HP) Outboard Powerhead (Cylinder Head, 1999 2005 Models)**

1. **Common and Widely Available** The 30/40HP Mercury outboard is one of the most popular small outboard engines, meaning parts, service manuals, and labor are readily accessible. This makes repairs and maintenance easier and more cost-effective.

2. **Proven Reliability** These engines were designed for durability and are known for lasting well with proper maintenance. Many still operate reliably after 20 years with regular upkeep.

3. **Affordable Replacement Parts** Since the engine is so common, replacement parts (cylinders, pistons, gaskets, etc.) are inexpensive compared to newer, high-performance outboards.

4. **Simple Design** The 30/40HP Mercury has a straightforward mechanical layout, making it easier for DIYers to work on without specialized tools or expertise.

5. **Good for Small Boats** Ideal for trolling, fishing, or small recreational boats where high horsepower isn t necessary. It provides sufficient power for its intended use.

6. **Aftermarket Support** There is a strong aftermarket community with upgrades (e.g., performance kits, fuel injection modifications) available if you want to enhance performance.

7. **Fuel Efficiency** Compared to larger outboards, the 30/40HP is fuel-efficient, making it cost-effective for occasional use.

8. **Resale Value** Even used, these engines hold value well if maintained, as they remain in demand for older boats.

1. **Age-Related Wear** Engines from this era (1999 2005) may have accumulated wear in critical components like the cylinder head, crankshaft, or bearings. A thorough inspection is essential before purchase.

2. **Potential Fuel Injection Issues** Later models in this range (especially post-2000) may have electronic fuel injection (EFI) systems that can fail or require recalibration. Mechanical carbureted versions are simpler but less efficient.

3. **Corrosion Risks** If the engine was stored improperly (e.g., in saltwater without flushing), internal corrosion could have damaged the cylinder head, pistons, or water pump.

4. **Limited Performance** At 30/40HP, this engine is not suited for high-speed or heavy-load applications. It may struggle with larger boats or rough water conditions.

5. **Electrical System Dependence** Some models rely on basic electrical systems (ignition, gauges) that may degrade over time, requiring occasional replacement of wiring or sensors.

6. **Environmental Regulations** Older outboards may not meet modern emissions standards if modified, which could restrict use in some areas.

7. **Labor Costs for Major Repairs** While parts are cheap, labor for overhauls (e.g., cylinder head replacement, crankshaft machining) can add up if professional help is needed.

8. **Potential for Hidden Damage** Without a pre-purchase inspection, issues like cracked heads, worn bearings, or fuel system leaks may not be immediately apparent.

---

### **Conclusion and Recommendation**

The **Mercury 893504T02 (30/40HP) outboard powerhead** is a solid, practical choice for small boats, fishing applications, or trolling, especially if you prioritize affordability, availability of parts, and simplicity. Its strengths lie in its reliability, cost-effectiveness, and ease of maintenance, making it a great option for DIYers or those on a budget.

**However**, the biggest drawbacks are its age-related wear risks and limited performance for demanding tasks. If you plan to use this engine long-term, **a thorough inspection is critical** focus on the cylinder head (for cracks or warping), pistons, bearings, and fuel system. Consider having a marine mechanic perform a **compression test, leak-down test, and visual inspection** before purchasing.

- **Buy if:** You need a reliable, low-maintenance engine for light-duty use (e.g., a small fishing boat, trolling, or a backup power source). You re prepared to invest time in maintenance or have access to a mechanic for inspections.

- **Avoid if:** You require high performance, plan to use it in rough conditions, or cannot afford potential major repairs. If you want a newer, more efficient engine, consider a **Mercury 40HP E-TEC (2006 ) or a Yamaha 30HP**, which offer better fuel injection and durability.

- **Best Approach:** Purchase from a reputable dealer or private seller who provides a **service history** and allows for a pre-purchase inspection. If buying used, prioritize engines with **documented maintenance** (oil changes, spark plug replacements, etc.).

Ultimately, this engine is a **great value for its intended use** but requires careful consideration of its age and condition before committing.

Details:

From Freshwater Boats hence, No Salt Corrosion. Please be certain this is the correct part for your motor. Throttle Lever PN 822682A stamped 822682-2. Complete Assembly including internal components rockers, cams, springs, intake valves, exhaust valves.

Genuine Mercury Marine Factory Original Parts COMPLETE Four Stroke 30/40hp Outboard Powerhead Component Cylinder Head and Cover Assembly, Includes Air Exhaust Intakes, Springs, Cams, Rocker Valves, Throttle Shift Levers, Driven Gear, Fuel Pump original Valve Bolts, From a Low Hour Freshwater good running 3-Cylinder 4 40hp 2000 Motor Electric, Carbureted model 40ELPT 4S / ELPT4 Group: 1F40412WD Serial Number: 0T086207 Assembly Part No. High Quality Previously-Owned Boat Parts. Cylinder Head related PN's: 834778T5, 877568T1, 877568T8. Cylinder Head Cover PN 893693A04 from 834779A1.

part #: 893504t02 prices

• $149.95-$750.69

specifications ouboaen:

• for makes: Mercury
• for years: 1999-2005
• mpn: 893504t02
• part type: Cylinder Head
• country of origin: United States
• please open and read sellers full item description: For Complete Product And Transaction Details. Thank You.
• customer service: 616 682-1560
• mfm return policy: For All Returns
• regardless of reason : Buyer To Pay Return Shipping Costs And A 20 Return Fee
• from outboard serial no.: 0t086207
• model group: 1f40412we 30 /40hp 4-stroke / Electric
• includes cylinder valve cover bolts: Original, Stainless Steel Attachment Bolts
• includes cylinder head cover: Part No. 893693a04
• throttle lever: 822682a2
• assembly is nla: No Longer Available, As No Longer Manufactured
• complete cylinder head assembly: Rockers, Cams, Intake And Exhaust Valves, Springs
• various mercury and mariner outboards: Including Some Big Foot Models
• driven gear: Part No. 833104t6 / T1
• from model no.: 40elpt 4s Elpt 4
• model years: 1999-2006
• michigan freshwater marine: Customer Service
• includes fuel pump: Part No. 826398t3
• shift lever: 825957 1, From A Good-running
• low hour outboard: 2000 40hp 3-cylinder 4-stroke Electric, Carbureted

seller ouboaen:

• city: Ada, Michigan
• # reviews: 4764
• rating: 100.0%

shipping ouboaen:

• cost: $0.00
• transit: 4-9 Days
• carrier: USPS
• type: Fixed
• service: USPS Priority Mail
• class: Expedited

offer ouboaen:

• sold: 0
• availability: In Stock
• quantity: 1
• started: May 9, 2026
• options: Ship-to-home

returns ouboaen:

• policy: Returns Accepted
• paid by: Buyer
• time: 30 Days

general ouboaen:

• Boat Parts > Outboard Engines Components > Powerhead Components
• condition: Used

payments ouboaen:

• wallet: Apple-pay
• other
• credit card: Diners-club

Mercury 893504T02 Is Similar To:

• 031026 Michigan Propeller Aluminum Prop Mercruiser Mercury Outboard (21.8% similar) Pb this prop has some minor damage as seen in the pictures. Please see included pictures. Condition: used but in good condition and guaranteed to function properly. This prop will also fit v6 Honda outboards with the correct hardware. 75 x 21P Mercuries mercury outboard propeller fits various ...(April 3rd, 2018)
• 06168-zy1-307 Honda Mercury Outboard Electric Circuit Breakers (36.6% similar) Products might fit other makes and model's, please research before assuming. Thanks in advance. Have up for sale good quality tested parts that a satisfactory guarantee. These products have been used and will average wear look feel to them...(April 9th, 2018)
• 10-30110 Mercury Lot Of Oem Outboard Screws New Free Shipping (35.5% similar) Lot of 2 oem mercury screws w lock washers used on some vintage mark outboard engines. Please verify comparability before purchase...(April 15th, 2018)
• 10-34691 Mercury Mariner Bulk Lot Pieces Old Stock Outboard Force Chrysler (44.2% similar) This is a bulk lot of new parts for mercury mariner force outboard nos nla 200 individual part numbers in factory bags with most being multi PACKS1500 total pieces packed USPS medium flat rate box flax...(February 9th, 2019)
• 10-38055 Mercury Lot Of Oem Outboard Hinge Plate Screws Quicksilver New (34.4% similar) This fee covers the initial shipping cost regardless of label free. Lot of 4 oem mercury outboard hinge plate screws - quicksilver please verify compatibility before purchase...(February 21st, 2019)
• 100-20-20 9737a7 9737a8 9737a9 9737a10 Mercury Hp Efi Powerhead Rebuild Kit Top Guided (30.1% similar) ...(October 28th, 2018)
• 100-25-20 6h4-11631-01-95 9009a5 9009a13 9009 Mercury Outboard Hp Bottom Guided Rebuild Kit (28.1% similar) ...(March 14th, 2018)
• 100-8m0057754 Mercury 2015 150 Four Stroke (29.5% similar) See pictures to rub mark where the paint is off on front lip of motor and really light marks clear other two close up. Otherwise the cowl is new and clean. Oem 8M0057754 mercury stroke cowl with blemish on front lip 150 four efi top hood cowling cover I'm pretty sure the lip part of painted cover ...(December 25th, 2016)
• 1004211wk Mercury 4 Hp Outboard (34.2% similar) It has been garaged stored up right and covered. For sale is a lightly used mercury 4 hp outboard motor model ml. This motor has not been operated in a while. I am the original owner and purchased this outboard new for use on my sailboat. The outboard model number is 1004211WK it considered a 2-...(July 12th, 2017)
• 10238367 Mercury Outboard Cylinder Head Block Water Jacket Cover (44.4% similar) Used cover from a 1978 mercury 115 horsepower 6 cylinder outboard boat motor...(February 1st, 2019)
• 10319 Stiletto Stainless Prop Mercury Yamaha Outboard Propeller (32.2% similar) Condition: used but in good condition and guaranteed to function properly. Part: 10319 stiletto stainless prop x 19P v6 mercury Yamaha outboard propeller fits various mariner motor parts. Please see included pictures...(August 24th, 2018)