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

3 Items

Set Descending Direction
View as List Grid
  1. 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.

    Learn More
    MSRP: $74.29 $55.57
    Add to Wishlist
  2. 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.

    Learn More
    MSRP: $38.39 $28.43
    Add to Wishlist
  3. Small Image
    10W-30 Catalyst Marine Engine Oil, 1 gallon | Sierra 18-9420CAT-3P
    SIERRA-18-9420CAT-3
    Qty In Stock: 67
    Brand: Sierra
    Sierra's Premium Blend 10W-30 catalyst engine oil is specially formulated to meet the needs of 4-stroke outboards with catalyst emission systems. Learn More
    MSRP: $39.99 $34.06
    Add to Wishlist

3 Items

Set Descending Direction
View as List Grid
Shop By
Now Shopping by
  1. Availability In Stock Remove This Item
  2. Brand Sierra Remove This Item
  3. Engine Cycle 4-Stroke Remove This Item
  4. Container Size 1 Gallon Remove This Item
Clear All
Shopping Options
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.