HOLIDAY ALERT

We will be closing at 12 PM EST on Friday, April 18th, in observance of Good Friday and Easter.
Any orders placed after this time will be processed on Monday, April 21st.
Have a happy Easter weekend!

Weather Closure Alert

Due to severe weather, our White House, Tennesee location will be closed Wednesday the 19th.

All shipments from this location will resume on Thursday the 20th. Thank you for your patience!

WE WANT TO HEAR FROM YOU!

We strive to make improvements that make it easier to serve your boating needs.
We’d like to know more about you and how we can do the best job possible for you.
Please take the time to complete this brief 3-5 minute survey to help us serve you better.

FREE Ground Shipping on Orders over $100!  Exceptions apply - see details.

Toggle Nav
  • Sign In
  • Create an Account
My Cart
Search
Menu
Account
Settings
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 1-12 of 13

Set Descending Direction
View as List Grid
Page
  1. Large
    1 Gallon 25W40 4-Stroke Marine Oil | Quicksilver 92-8M0078620
    QS-92-8M0078620
    Qty In Stock: 266
    Brand: Quicksilver

    1 Gallon 25W40 4-Stroke Marine Oil

    Learn More
    MSRP: $34.09 $30.99
    Add to Wishlist
  2. Small
    25W40 4-Stroke Synthetic Blend Marine Oil | Quicksilver 92-8M0078623
    QS-92-8M0078623
    Qty In Stock: 243
    Brand: Quicksilver

    1 gallon 25W40 4-Stroke Synthetic Blend Marine Oil

    Learn More
    MSRP: $46.19 $41.99
    Add to Wishlist
  3. Small Image
    25W-40 4-Stroke Marine Engine Oil, 1 quart | Sierra 18-9400-2
    SIERRA-18-9400-2
    Qty In Stock: 185
    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
    Add to Wishlist
  4. Small Image
    25W-40 Catalyst Marine Engine Oil, 1 quart | Sierra 18-9400CAT-2
    SIERRA-18-9400CAT-2
    Qty In Stock: 131
    Brand: Sierra

    Premium Blend 25W-40 catalyst engine oil specially formulated to meet the needs of 4-stroke marine engines with catalyst emission systems

    Learn More
    MSRP: $12.69 $10.81
    Add to Wishlist
  5. Small Image
    25W-40 Catalyst Marine Engine Oil, 1 quart | Sierra 18-9440CAT-2
    SIERRA-18-9440CAT-2
    Qty In Stock: 133
    Brand: Sierra
    Synthetic blend 25W-40 engine oil is formulated for stern drive & inboard marine engines with catalyst emission systems. Learn More
    MSRP: $16.49 $9.99
    Add to Wishlist
  6. Small Image
    25W-40 Synthetic Blend Oil, 5 quart | Sierra 18-9440-4
    SIERRA-18-9440-4
    Qty In Stock: 118
    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
  7. Small
    1 quart 25W40 4-Stroke Marine Oil | Quicksilver 92-8M0078619
    QS-92-8M0078619
    Qty In Stock: 173
    Brand: Quicksilver

    1 quart 25W40 4-Stroke Marine Oil

    Learn More
    MSRP: $12.09 $10.99
    Add to Wishlist
  8. 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: 143
    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.

    Learn More
    MSRP: $74.39 $46.29
    Add to Wishlist
  9. Small Image
    25W-40 Catalyst Marine Engine Oil, 5 quart | Sierra 18-9400CAT-4
    SIERRA-18-9400CAT-4
    Qty In Stock: 165
    Brand: Sierra
    Sierra's Premium Blend 25W-40 catalyst engine oil is specially formulated to meet the needs of 4-stroke marine engines with catalyst emission systems. Learn More
    MSRP: $57.69 $38.66
    Add to Wishlist
  10. 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
    Add to Wishlist
  11. Small
    1 quart 25W40 4-Stroke Synthetic Blend Marine Oil | Quicksilver 92-8M0078622
    QS-92-8M0078622
    Qty In Stock: 148
    Brand: Quicksilver

    1 quart 25W40 4-Stroke Synthetic Blend Marine Oil

    Learn More
    MSRP: $14.29 $12.99
    Add to Wishlist
  12. 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: 284
    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
    Add to Wishlist

Items 1-12 of 13

Set Descending Direction
View as List Grid
Page
My Wish List
Last Added Items
  1. Add to Cart
    Remove This Item
Go to Wish List
You have no items in your wish list.
© 2025 Marine Parts Source. All Rights Reserved.