PRODUCT DETAILS
Ignition Coil for Mercury / Mariner OptiMax & EFI Outboards
High-quality marine-grade aftermarket 5-pin ignition coil for selected Mercury and Mariner OptiMax, EFI and Racing outboards.
Suitable for a wide range of selected 30 HP–300 HP applications where the original ignition coil cross-references to 8M0077471 / 879984T01.
Fitment
Mercury OptiMax – Selected Models
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75 HP
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90 HP
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115 HP
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125 HP
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200 HP
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225 HP
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250 HP
Selected 75 / 90 / 115 HP 3-cylinder OptiMax applications use this coil from approximately 2004 onwards.
OptiMax Pro XS – Selected Models
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115 Pro XS
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175 Pro XS
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200 Pro XS
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225 Pro XS
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250 Pro XS
OptiMax / Racing – Selected Models
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225 XS
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225 Sport XS
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250 XS
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250 Sport XS
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300 XS
EFI 2-Stroke – Selected Models
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150 HP – 2.5L EFI
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175 HP – 2.5L EFI
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200 HP – 2.5L / 3.0L EFI
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225 HP – 3.0L EFI
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250 HP – 3.0L EFI
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Selected 225X / 300X Racing EFI
EFI 4-Stroke – Selected Applications
Also cross-referenced for selected:
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30 HP
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40 HP
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50 HP
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60 HP
⚠️ This does NOT fit every Mercury / Mariner engine within the 30–300 HP range.
Always check the original coil number and engine serial number.
Replaces Mercury / Mariner Part Numbers
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300-8M0077471
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8M0077471
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300-879984T01
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879984T01
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339-879984T00
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879984T00
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339-879984A1
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879984A1
Searchable Numbers
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3008M0077471
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300879984T01
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339879984T00
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339879984A1
Mercury identifies 8M0077471 as the superseding replacement for 879984T01, 879984T00 and 879984A1.
Product Features
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5-pin connector
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12V ignition coil
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Mercury / Mariner applications
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Selected OptiMax / Pro XS / EFI / Racing
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Selected 2-stroke & 4-stroke applications
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Marine-grade aftermarket replacement
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Direct replacement where part number matches
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New
Please Note
Replacement coils may have a different number or revision marking moulded/stamped into the body.
This is normal with superseded/replacement components and the marking alone should not be used to determine compatibility.
What's Included
1 × Ignition Coil
This listing is for ONE coil only.
⚠️ Important – Check Compatibility
Mercury used several very similar-looking ignition coils.
Before ordering, please check:
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Original ignition coil part number
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5-pin electrical connector
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Engine horsepower
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Complete serial number
If the coil looks the same as yours, this does not always mean it is the correct one for your outboard.
If unsure, send SSI Marine your engine horsepower + complete serial number + original coil number and we will help check compatibility.
Buyer Responsibility
It is the buyer's responsibility to confirm compatibility before purchasing.
Correct diagnosis is recommended before replacing ignition components, as spark plugs, wiring, trigger/stator or other electrical faults can produce similar symptoms.
Why Buy From SSI Marine?
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Marine-grade aftermarket & OEM-spec parts
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Workshop-tested products
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More than 10 years supplying outboard parts
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Same-day dispatch before 1 PM Monday–Friday
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Royal Mail Tracked 24
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UK stock – collection from Leigh
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Technical support from experienced outboard specialists
SHIPPING & DELIVERY
Delivery & Returns Policy
Delivery
Standard Delivery
- £6: Royal Mail Tracked 24 Service
- £3.99: Large Letter - Royal Mail 1st Class Post (Untracked)
We offer free delivery on all orders over £150 (excludes outboard engines).
Orders placed before 1:00 PM (Monday-Friday) are usually dispatched the same working day.
Most parcels are delivered within 24 hours, but please allow extra time for courier delays that may occur outside our control.
For outboard engines, please contact us for a delivery quote.
Important: Please ensure your shipping address is correct before completing checkout. SSI Marine is not responsible for parcels sent to an incorrect address provided by the buyer.
Tracking Your Order
Once your order has been dispatched, you will receive a tracking number via email (after 5 PM on the day of dispatch).
Tracking is available only for parcels sent via Royal Mail Tracked 24.
Large Letter orders are sent via Royal Mail 1st Class Post (untracked).
Returns
We accept returns of unused and undamaged items within 30 days of purchase.
Returned items must be in sellable condition and include the original packaging.
Please do not tape, label, or write directly on the product's original box.
Important: Do not return items in their original product boxes only, they must be placed inside a protective outer box or bag. Parcels returned like the example below will be subject to a 20% restocking fee.
Return shipping costs are the customer's responsibility.
Please include your order details and reason for return inside the parcel.
Refunds
Refunds are issued for the item purchase price only (shipping costs are non-refundable).
All refunds will be made using the same payment method as your original order.
Items returned in poor condition or without proper packaging may incur a 20% restocking fee.
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