S2K Commerce - Products Dropdown
Actions
S2K Commerce - Order Entry
Actions
187151
805225A1
8M0041517
8M0041571
8M0222278
892811T01
892811T02
988181
892123
892123001
892123002
18715
18715T
840481T01
840481001
883381
Mercury Fuel System
Mercury 2.5L Optimax DFI Fuel Injector 804841
Mercury 804841 is a fuel injector used on select 2.5L DFI and Optimax outboard engines. It is commonly found in the fuel rail assembly on 110-200HP direct fuel injection two-stroke powerheads.
This injector is commonly associated with V-115, V-135, V-150, V-175, and 200HP DFI applications, including some XS, Racing, Sport Jet, M2 Jet Drive, and select 3.0L DSI models. Because injector usage can vary by serial number, verify your OEM diagram before ordering.
Compatible Applications
| Brand | Engine / System | Application | Fitment Note |
|---|---|---|---|
| Mercury / Mariner | 2.5L DFI / Optimax 110-200HP | Fuel rail injector | Verify by serial number and injector location |
| Mercury / Mariner | V-115, V-135, V-150, V-175 DFI | Direct fuel injection system | Used where OEM number 804841 is listed |
| Mercury | 200 DFI Sport Jet and M2 Jet Drive | Fuel injector / fuel rail assembly | Confirm by jet drive model and serial number |
| Mercury | Select 3.0L DSI applications | Fuel injection system | Verify exact engine diagram before ordering |
Important Fitment Note
DFI fuel injectors can vary by engine family, serial number, cylinder location, and fuel rail assembly. Always confirm compatibility using your engine serial number, model, and existing injector part number before ordering.
OEM & Cross Reference Numbers
| Mercury OEM Number | 804841 |
| Description | Fuel Injector |
| Known Supersessions | No supersession provided |
What This Part Is Used For
This fuel injector meters fuel into the direct fuel injection system on select Mercury DFI and Optimax engines. It works as part of the fuel rail assembly to help deliver the correct fuel amount for combustion.
A worn, clogged, leaking, or failed injector can cause rough running, hard starting, poor acceleration, excessive fuel use, misfires, or engine fault codes. Injector replacement should be matched to the correct OEM part number and engine serial number.
Key Features and Benefits
- Fuel injector for select Mercury and Mariner DFI / Optimax outboards
- Commonly used on 2.5L 110-200HP direct fuel injection engines
- Fits select V-115, V-135, V-150, V-175, and 200HP DFI applications
- Also associated with some Sport Jet, M2 Jet Drive, XS, Racing, and 3.0L DSI models
- Important replacement part for restoring proper fuel delivery
- Sold individually unless otherwise stated on the product page
FAQ
What is Mercury 804841?
Mercury 804841 is a fuel injector used on select DFI and Optimax fuel injection systems.
Does this fit all Optimax engines?
No. It fits select 2.5L DFI / Optimax engines and some related applications. Always confirm by engine serial number and OEM parts diagram.
What symptoms can a bad injector cause?
A faulty injector may cause rough idle, hard starting, poor acceleration, misfires, excessive fuel consumption, or engine performance issues.
Should injectors be matched by serial number?
Yes. DFI injector applications can be specific to engine model, serial range, and fuel rail configuration. Serial number verification is recommended before ordering.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer, technician, boat builder, or industry professional? We offer dealer pricing for qualified marine businesses.
Shipping Policy
- Free shipping on orders over $100 continental U.S.
- Orders ship via UPS, USPS, and FedEx.
- Orders received before 5:30 PM EST ship the same business day.
- Typical delivery time is 1-5 business days.
30-Day Return Policy
- Returns accepted within 30 days of delivery.
- Parts must be new, unused, and in original packaging.
- Installed parts are not returnable.
- Return authorization is required before sending items back.
Need help with a return or order question?
Contact Us
Phone: 941-721-3000
Searchable Terms
Mercury fuel injector, Mercury Optimax injector, Mercury DFI injector, Mercury 2.5L DFI fuel injector, Mercury 115 DFI injector, Mercury 135 DFI injector, Mercury 150 DFI injector, Mercury 175 DFI injector, Mercury 200 DFI injector, Mercury Sport Jet injector, M2 Jet Drive injector
Searchable Part Numbers
804841
8M0222157
804528
Fits Mercury 75-250 HP DFI Outboards
Compatible with select Mercury 75-250 HP DFI outboard engines using injector #840481 and #804528. The Pro Marine 20-3071B Fuel Injector O-Ring is a replacement injector seal designed to maintain a proper seal around the fuel injector. It is associated with Manufacturer Item 804529 and is commonly searched by that number when replacing worn injector seals during fuel system service.
Compatibility
This injector O-ring is used on many Mercury DFI / Optimax outboards from 75 HP up to 250 HP. It is associated with OEM reference number 804529 and commonly used with fuel injectors 840481 and 804528.
Application Chart
Always confirm compatibility using your engine model, serial number, injector number, or existing part number before ordering.
Part Numbers & Cross References
| Reference Type | Part Number |
|---|---|
| Pro Marine Part | 20-3071B |
| Manufacturer Item | 804529 |
| Cross Reference # | 804529 |
| Fits Injector # | 840481 |
| Fits Injector # | 804528 |
What This Part Is Used For
Fuel injector O-rings help seal the injector properly when installed in the fuel rail or intake system. If an injector is removed for cleaning, inspection, or replacement, installing a new O-ring helps ensure the system seals correctly when reassembled.
Over time these seals can flatten, harden, or become damaged due to heat and fuel exposure. Replacing them during injector service helps prevent sealing issues and keeps fuel system maintenance reliable.
Frequently Asked Questions
What engines does this O-ring fit?
This part is listed for Mercury 75-250 HP DFI outboards and fits injector numbers 840481 and 804528.
What OEM number is associated with this part?
The product page lists both Manufacturer Item 804529 and Cross Reference #804529.
When should I replace a fuel injector O-ring?
Injector O-rings are commonly replaced anytime injectors are removed for cleaning, inspection, or replacement.
Is this an OEM Mercury part?
This listing is an aftermarket replacement part from Pro Marine associated with Mercury reference number 804529.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer, technician, boat builder, or industry professional? We offer dealer pricing for qualified marine businesses.
Shipping Policy
- Free shipping on qualifying orders over $100 (continental U.S.).
- Orders ship via UPS, USPS, or FedEx.
- Orders received before 5:30 PM EST ship the same business day.
- Typical ground delivery time is 15 business days.
30-Day Return Policy
- Returns accepted within 30 days of delivery.
- Items must be new, unused, and in original packaging.
- Return authorization is required before sending items back.
Need help with a return or order question?
Contact Us
Phone: 941-721-3000
Searchable Part Numbers
Pro Marine Part: 20-3071B
Manufacturer Item: 804529
Cross Reference #: 804529
Fits Injector #: 840481, 804528
Common Search Terms: 20-3071B fuel injector o-ring, Mercury 804529, Mercury injector o-ring 804529, injector 840481 seal, injector 804528 o-ring
