Sea-Dog Inboard Motor Flush - P/N 521550-1

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RRP$22.26 $22.00
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Unit of Measure
Alternate Products SKU
"18-9009", "5-53299", "3-521550-1"
Manufacturer Part Number (MPN)

Do you have problems with stains from salt, sand, minerals that contaminate the quality of your boat’s cooling systems? Your boat needs the best value of a product that will ensure excellent results from your chosen manufacturer. Worry-less Sea-Dog Line got your back.

Sea-Dog Line-made Motor Flush Inboard allows quick flushes away briny, sand strands, mineral crystals, and contaminates from your lower cooling system unit. Motor Flush Inboard helps extend the engine’s service life.

Motor Flush Inboard is easy to use by;

  • fitting the rubber cup over the water intake,
  • connecting a garden hose, and
  • Extend the aluminum leg to seal the cup to the hull.

Key Features:

  • Molded Rubber/Aluminum
  • Great for winterizing and tune-ups.
  • Easy to use and flexible.
  • Great use for wintertime, tune-ups, and other maintenance that requires running an inboard engine out of the water.
  • Freshwater flushes the cooling system, no tools are required.


  • UPC:035514521451
  • Weight:1.08 LBS A:15 ½ inches B:27 ½ inches
  • Brand: Sea-Dog Line
  • This product replaces: 521550-1, 521550, 3-521550, 35514521451

Molded Rubber/Aluminum.

This product replaces:

    521550-1, 521550, 3-521550, 35514521451

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ProPride 3P Hitch, Hassle Free, 60-Day No Risk Guarantee

You can return the 3P Hitch at any time during the first 60 days of use for a complete refund. That's a 100% risk free guarantee. 60 days begins when you receive the product unless otherwise arranged for a later date. We must receive the product in Holly, MI in 60 days or less. To initiate a return you can contact us for a return merchandise authorization. If the hitch was purchased during a FREE shipping promotion, $299 will be deducted for any returned hitches.


We can ship to virtually any address in the Continental US. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

Returns Policy

You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.)

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, please Contact Us with your order number and details about the product you would like to return. We will respond quickly with instructions for how to return items from your order.

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