
805243A12 Comparison
| photo | price | summary | rating |
|---|---|---|---|
![]() | $145.00 | Condition is Used, MerCruiser 805243A12 Throttle Body Assembly 454 / 502 MPI MAG 805243, shipping cost = $18.00 | 98.9% |
![]() | $165.00 | Condition is Used, MerCruiser 805243A12 Throttle Body 7.4L 454 8.2L 502, FREE SHIPPING | 95.5% |
![]() | $199.99 | Condition is Used, Mercury Marine MerCruiser 805243A12 Throttle Body OEM MERC GT-8206, FREE SHIPPING | 100.0% |
![]() | $214.00 | Condition is Used, OEM Mercruiser 1993 1994 - 1996 Throttle Body 454 502 EFI 7.4L MPI FRESHWATER, FREE SHIPPING | 99.8% |

The Mercruiser 805243A12 Throttle Body is a crucial component in the MPI (Multi-Point Fuel Injection) system of MerCruiser 454 and 502 engines. This throttle body, specifically designed for marine applications, is engineered to deliver optimal engine performance and responsiveness.
The 805243A12 Throttle Body features an electronic throttle control system that allows for precise throttle and shift control. This system enables smoother acceleration, improved fuel efficiency, and reduced engine emissions. The throttle body also includes a built-in idling control valve, which maintains stable engine speed during idle conditions, ensuring a more comfortable boating experience.
The 805243A12 Throttle Body is constructed of high-quality materials, including a durable cast aluminum housing, stainless steel throttle plate and lever, and hard-coated throttle valve shaft. These materials provide excellent corrosion resistance, ensuring long-lasting performance even in the harsh marine environment.
The throttle body comes with a factory-set calibration for the specific engine application, ensuring optimal fuel delivery and engine performance right out of the box. However, it is important to note that the use of non-approved fuel additives, improper installation, or modifications to the engine may require calibration adjustments.
Installation of the 805243A12 Throttle Body is relatively straightforward, with clear installation instructions provided in the package. It is essential to follow these instructions carefully to ensure proper installation and to avoid any potential issues.
In conclusion, the Mercruiser 805243A12 Throttle Body is a high-performance, reliable, and durable component designed for marine engines. Its advanced electronic control system, combined with its high-quality materials and factory-set calibration, make it an excellent choice for boaters seeking optimal engine performance, responsiveness, and ease of operation.
Pros and Cons of Buying Mercruiser 805243a12 Throttle Body for 454 502 MPI Mag Engine
The Mercruiser 805243a12 Throttle Body is a crucial component for the 454 502 MPI Mag engine. It plays a significant role in controlling the engine's fuel delivery and throttle response. In this context, let's discuss the potential advantages and disadvantages of purchasing this throttle body.
Pros:1. Improved Fuel Efficiency: A new throttle body can result in improved fuel efficiency due to better fuel metering and delivery, which can lead to cost savings in the long run.
2. Enhanced Throttle Response: A new throttle body can provide quicker and more responsive throttle control, improving overall engine performance and driving experience.
3. Better Idle Stability: A well-functioning throttle body can help maintain consistent engine idle, preventing surging and rough idling.
4. Reduced Emissions: By improving fuel efficiency and combustion, a new throttle body can help reduce engine emissions, making your boat more eco-friendly.
Cons:1. Cost: Replacing a throttle body can be an expensive investment, especially for high-performance engines like the Mercruiser 454 502 MPI Mag.
2. Installation Complexity: Installing a new throttle body can be a complex process, requiring specialized tools and mechanical expertise. It may be best to have it installed by a professional mechanic or boat service center.
3. Potential for OEM Compatibility Issues: Some aftermarket throttle bodies may not be fully compatible with the OEM engine system, leading to potential issues and additional costs for modifications.
Conclusion:The Mercruiser 805243a12 Throttle Body offers several advantages, including improved fuel efficiency, enhanced throttle response, better idle stability, and reduced emissions. However, its high cost, installation complexity, and potential compatibility issues are significant drawbacks.
Recommendation:If you experience issues with your Mercruiser 454 502 MPI Mag engine's throttle body, such as poor fuel efficiency, rough idling, or sluggish throttle response, it may be worth considering a replacement. However, we recommend consulting with a professional mechanic or boat service center to assess the situation and determine if a new throttle body is the best solution. They can help you weigh the benefits against the costs and consider alternative options, such as throttle body repairs or adjustments. Ultimately, a well-maintained engine and regular servicing can help minimize the need for costly component replacements.
Details:
Clearing out old inventory, complete as seen in photo. Shipped USPS excellent condition for its age. Mercruiser 805243A12 throttle body assembly 454 / 502 mpi mag 805243, clean used running take off from fresh water cooled engine, vst fuel system Sn# ok147349 below excellent condition for its age. Oem Mercruiser, boxed and moved around parts department shelves for years, please see pictures.
specifications inboardfuel:
- for models: 454
- brand: Mercruiser
- mpn: 805243a12
- part type: Throttle
- country of origin: United States
payments inboardfuel:
- credit card: discover
- wallet: paypal
- other
shipping inboardfuel:
- class: expedited
- transit: 3-8 days
- type: fixed
- carrier: usps
- service: usps priority mail
general inboardfuel:
- category: Boat Parts > Inboard Engines Components > Intake Fuel Systems
returns inboardfuel:
- paid by: seller
- policy: returns accepted
- time: 30 days
offer inboardfuel:
- sold #: 10
- started: march 24, 2026
- options: ship-to-home
- availability: in stock
- prices: $145.00–$214.00
- item condition: Used
- in stock #: 4
seller inboardfuel:
- rating: 100.0%
- city: farmingdale, new jersey
- # reviews: 871
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