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Inboard & I/O Engine Parts

Inboard Marine Engine Parts and Accessories

As the largest online dealer of inboard boat parts, Marine Parts Source will help you find the right engine parts you need for any project. We’re here to assist with seasonal maintenance, major repairs and more so you can get back on the water. Use our convenient categories to browse our collection — or if you know the part number you need, enter it into the search bar. From oil and fuel filters to spark plugs, exhaust manifolds, bell housings, starters and alternator belts, we supply boat owners from coast to coast.

You can always count on quality and knowledge when you shop with us. We’re an authorized dealer of the leading OEM and aftermarket performance inboard marine brands, including J&N Electric, Sierra, Arco Marine, Volvo Penta and Crusader. If you have a question, our sales associates have the technical expertise to answer it. Enjoy free ground shipping on qualifying orders so your vessel is ready for adventure.

Inboard & I/O Engine Parts

Items 13-24 of 30

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    25W-40 Marine Engine Oil, 1 quart | Sierra 18-9440-2P
    SIERRA-18-9440-2
    Qty In Stock: 98
    Brand: Sierra

    Synthetic blend 25W-40 engine oil formulated for stern drive & inboard marine engines

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    MSRP: $17.89 $10.89
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  2. Small Image
    1 quart 10W-40 Full Synthetic Engine Oil | Volvo Penta 21681794
    VOLVO-21681794
    Qty In Stock: 842
    Brand: Volvo Penta
    OEM 21681794 Volvo Penta 10W-40 synthetic oil is formulated for gasoline marine engines to provide maximum protection against wear under severe running conditions. Learn More
    MSRP: $15.90 $15.86
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  3. Sierra 18-9690-3 4 Stroke Full Synthetic Oil 10W-30, 1 quart
    4 Stroke Full Synthetic Oil 10W-30, 1 Gallon | Sierra 18-9690-3
    SIERRA-18-9690-3
    Qty In Stock: 5
    Brand: Sierra

    Sierra's full synthetic engine oil optimizes engine life by reducing friction while providing wear protection in severe operating conditions. Used with outboard and sterndrive applications.

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    MSRP: $74.29 $55.57
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  4. Sierra 18-9440CAT-4 25W-40 Synthetic Blend Catalyst Engine Oil - 5 qt.
    25W-40 Synthetic Blend Catalyst Engine Oil, 5 quart | Sierra 18-9440CAT-4
    SIERRA-18-9440CAT-4
    Qty In Stock: 132
    Brand: Sierra

    Synthetic blend 25W-40 engine oil is formulated for all 4-stroke applications including outboard, sterndrive, and inboard marine engines with catalyst emission systems. NMMA FC-W/API-SL certified and approved.

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    MSRP: $74.39 $46.29
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  5. Small Image
    25W-40 4-Stroke Marine Engine Oil, 1 quart | Sierra 18-9400-2
    SIERRA-18-9400-2
    Qty In Stock: 139
    Brand: Sierra
    Sierra's Premium Blend engine oil is specially formulated to meet the needs of inboard & stern drive marine engines. Learn More
    MSRP: $14.99 $9.79
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  6. Small Image
    25W-40 Premium Blend Inboard Engine Oil, 55 gallon | Sierra 18-9400-7
    SIERRA-18-9400-7
    Qty In Stock: 0
    Brand: Sierra
    25W-40 Premium Blend Inboard Engine Oil, 55 gallon Learn More
    MSRP: $2,564.19 $1,731.72
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  7. Small
    1 quart 25W40 4-Stroke Synthetic Blend Marine Oil | Quicksilver 92-8M0078622
    QS-92-8M0078622
    Qty In Stock: 149
    Brand: Quicksilver

    1 quart 25W40 4-Stroke Synthetic Blend Marine Oil

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    MSRP: $14.29 $12.99
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  8. Sierra 18-9553-3 Premium Blend Diesel Marine Engine Oil 15W-40 - 1 Gallon
    Premium Blend Diesel Marine Engine Oil 15W-40 - 1 Gallon | Sierra 18-9553-3
    SIERRA-18-9553-3
    Qty In Stock: 62
    Brand: Sierra

    Premium blend 15W-40 oil is specially formulated to meet the highest standards of diesel marine engine oil.

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    MSRP: $38.39 $28.43
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  9. sierra-25W-40-4-stroke-engine-oil-5QT-18-9400-4
    4-Stroke Premium Blend Marine Engine Oil 25W-40 - 5 Quart | Sierra 18-9400-4
    SIERRA-18-9400-4
    Qty In Stock: 280
    Brand: Sierra
    Sierra's Premium Blend 25W-40 engine oil is specially formulated to meet the needs of inboard & stern drive marine engines. Learn More
    MSRP: $67.29 $46.90
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  10. Small Image
    25W-40 Synthetic Blend Oil, 5 quart | Sierra 18-9440-4
    SIERRA-18-9440-4
    Qty In Stock: 87
    Brand: Sierra

    Synthetic blend 25W-40 engine oil formulated for stern drive & inboard marine engines

    Learn More
    MSRP: $83.69 $53.54
    Add to Wishlist
  11. QS QT Premier Full Synthetic 10W30 oil
    Premier 10W30 Full Synthetic Marine Oil, 1 Quart | Quicksilver 92-8M0175780
    QS-92-8M0175780
    Qty In Stock: 13
    Brand: Quicksilver

    Premier 10W30 Full Synthetic Marine Oil, 1 quart. Not for use with catalyst engines.

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    MSRP: $17.59 $15.99
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  12. Small
    1 quart 25W40 4-Stroke Marine Oil | Quicksilver 92-8M0078619
    QS-92-8M0078619
    Qty In Stock: 177
    Brand: Quicksilver

    1 quart 25W40 4-Stroke Marine Oil

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    MSRP: $32.99 $29.99
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Items 13-24 of 30

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