Fuel Injector Seal Kit – Fits MerCruiser (Replaces 9-33302)

$3.50 $5.00

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Product Details

This Fuel Injector Seal Kit is designed for a range of MerCruiser MPI engines produced between 1998 and 2001, including the 350 Magnum, MX 6.2L, 454 Magnum, 502 Magnum, and 8.2L MPI sterndrive and inboard models. The kit provides the necessary seals to ensure a leak-free connection, restoring fuel system integrity and engine performance.

It serves as a direct replacement for MerCruiser part number 9-33302.

Engineered for a direct replacement fit.
Specifically designed for gasoline Multi-Port Injection (MPI) systems.
Covered by a 1-year warranty from The ROP Shop for peace of mind.

Part Number Matrix

Use this matrix to confirm equivalent references across OEM and aftermarket.

Brand	Part Number
MerCruiser	9-33302

Engine & Model Compatibility

Confirm your engine model/year in the table below.

This kit is specifically designed for the following MerCruiser engines.

Brand	Model	Rated HP	Stroke	Years	OEM Part No.	Notes
MerCruiser	350 Magnum MPI	Varies	4-Stroke	1998–2001	9-33302	Sterndrive & inboard engines
MerCruiser	MX 6.2L MPI	Varies	4-Stroke	1998–2001	9-33302	Sterndrive & inboard engines
MerCruiser	454 Magnum MPI	Varies	4-Stroke	1999–2001	9-33302	Sterndrive & inboard engines
MerCruiser	502 Magnum MPI	Varies	4-Stroke	1999–2001	9-33302	Sterndrive & inboard engines
MerCruiser	8.2L MPI	Varies	4-Stroke	1999–2001	9-33302	Sterndrive & inboard engines

Technical Specs

Product Type: Fuel Injector Seal Kit
Installation: Direct replacement
Fuel Type: Gasoline
Housing Material: Rubber/Polymer
Dimensions: 4.0" x 1.0" x 4.0"
Warranty: 1 year (The ROP Shop)
Other Technical Attributes: Designed for MPI (Multi-Port Injection) systems

What’s in the Box

Fuel Injector Seals (Replaces 9-33302)

Installation Notes

Safely relieve all pressure from the fuel system before beginning work.
Disconnect the boat's battery.
Thoroughly clean the area around the fuel rail and injectors to prevent contamination.
Carefully disconnect the electrical connectors and fuel lines from the injectors.
Remove the fuel rail mounting bolts and lift the rail with injectors attached.
Gently remove the old, hardened seals from each injector.
Lightly lubricate the new seals with clean engine oil or a fuel-safe lubricant.
Install the new seals onto the injectors, ensuring they are seated correctly.
Reinstall the fuel rail and injectors, torquing bolts to manufacturer specifications.
Reconnect all fuel lines and electrical connectors.
Reconnect the battery.
Turn the ignition key to the ON position (do not start) to pressurize the system and carefully inspect for any leaks before starting the engine.

Troubleshooting & FAQ

How do I know if my fuel injector seals are failing?

Common signs of failing fuel injector seals include a strong smell of gasoline around the engine bay, visible fuel leaks near the injector base, poor engine performance, rough idling, hesitation during acceleration, and decreased fuel efficiency.

Is this kit compatible with Throttle Body Injection (TBI) systems?

No, this seal kit is specifically designed for Multi-Port Injection (MPI) systems as listed in the compatibility chart. It is not suitable for TBI applications.

What is the recommended replacement interval for these seals?

There is no fixed replacement interval, but it is best practice to replace injector seals whenever the fuel injectors or fuel rail are removed for service. They should also be replaced immediately if any signs of leaking or degradation are discovered.

Do I need special tools to install this seal kit?

While basic hand tools are required, a fuel pressure gauge is necessary to safely relieve system pressure. A small pick or hook tool can also be helpful for removing old, brittle seals without damaging the injector housing.

How does this aftermarket kit compare to the OEM MerCruiser part?

This kit is engineered to meet or exceed OEM specifications for fit, material composition, and durability. It provides a reliable seal for the fuel system at a competitive price point, offering comparable performance to the original part.

OEM vs. Aftermarket?

This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.

Shipping speed & cost

We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.

Warranty & returns

Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.

Safety & Important Info

Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
This is an aftermarket replacement, not an OEM component.
Professional installation is recommended for safety and performance.

About Sea Sierra

Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.

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