Free Shipping!
On All Orders Over $99*

click to zoom in

have questions?

Mercury Prop Nut - Sierra Marine Engine Parts - 18-3704 (118-3704)

(No reviews yet) Write a Review
0.10 LBS
Manufacturer Part Number (MPN):

Mercury Prop Nut - Sierra Marine Engine Parts - 18-3704 (118-3704)


Why would you want a loose nut? You don't want your propeller to wobble on open water. Sierra 18-3704 Prop Nut, Prop Nut for Mercury, and Mariner Outboards For 35-70HP. Propeller nuts are used to secure the propeller against the shaft tape. Utilize this big marine part to make the most of your time on the water. Whether you're practicing your casting, exploring to see the magnificent underwater, or simply sailing on the open ocean for pleasure, you must equip your vessel with the best equipment to guarantee that nothing ruins your incredible leisure experience.

Key Features:

  • Genuine OEM part, not an aftermarket part
  • Utilizing abrasion-resistant materials to ensure optimal longevity
  • Expertly crafted from high-quality materials
  • Conforming to stringent quality standards
  • Compatible with GLM 21240 ; Mallory 9-73901 ; Mercury Marine 11-69578; 11-69578A1; 11-69578A2 and 11-69578Q1


  • Brand: Sea Star Solutions
  • SKU: 18-3704
  • UPC: 030999236975
  • Weight: 0.10 LBS
  • Manufacturer Part Number (MPN): 118-3704
  • Type: Prop Hardware
  • Part Type: Marine Drive Unit Components

Prop Nut fitting Mercury Outboard 30-70hp applications

This product replaces:

    47-3704, GLM21240, 11-69578, 11-31990, AP123, 3099923697, 30999236975, 92-21240D, 9-73901


We can ship to virtually any address in the 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.

Need help? We're available at+1 (800) 664-8116 - Email us
to top