Where to buy Engine SuppliesCold weather right around the corner for much of the country which, sadly, means it is time to winterize your boat motor for the off season. If you are a “do-it-yourselfer” and appreciate saving a little money, then this article is for you.  The following are my top 5 places to purchase engine supplies based on an in-depth analysis of online merchants.

If you are in a hurry and want to skip the details and just get to the top 5, then click here.  Otherwise, continue on to see how I evaluated the online merchants and how the prices compared before I get to my recommendations.

The Evaluation Process

For this evaluation, I considered four key factors:

  • Relative Prices. Using a Mercury 150 Four-Stroke and a Yamaha F150 as an example, I identified the key engine supplies (Oil, Filter, Gear Lube) and quantities recommended by each manufacturer.  I then shopped for the required items at each merchant and calculated the total price, including shipping. Only OEM products were included, no aftermarket substitutes.
  • Type of Business. A dealership or distribution center that has invested in inventory and a fulfillment process will often provide better customer service and more timely deliveries than a “drop shipper” business that is simply taking and forwarding orders for someone else to fulfill.
  • Ease of Shopping. Some sites are far better than others in terms of helping you locate the items you need.  I searched for the Mercury and Yamaha supplies using both part numbers (e.g., 92-8M0078630) and keywords (Mercury 25W-40 Synthetic Blend) and calculated the percentage of successes. Being able to easily locate the correct parts is about saving time and minimizing confusion.
  • Satisfaction Ratings: Getting the best prices isn’t always the best move if it means frustration or delays in getting your shipment.   Reviews by Google, Trust Pilot or the Better Business Bureau were examined to determine whether each merchant is likely to give you a positive experience.

Price Comparison

Of course, a key driver of my rankings are the prices.  A company that offers lower prices will naturally get ranked higher provided that the other factors suggest that they can reliably fulfill their commitments.

As noted earlier, I evaluated the prices for the needed maintenance items for both a Mercury and a Yamaha 150 four-stroke.  It turns out that some companies might be competitive with one engine brand but not the other.  Let’s start by looking at the prices for the Mercury items.  Please note that these prices are from early October, 2023 and are subject to change.

Mercury Maintenance Items

For the Mercury 150 4-stroke, I chose the Mercury 25W-40 Synthetic Blend oil which is what I use on my boat.  The engine requires 6.34 quarts of oil and so I selected two gallons (8 quarts) which is often more economical than buying 7 separate quarts.  I also selected one Mercury Oil Filter and one quart of Mercury High Performance (SAE 90) Gear Lube since that is the recommended choice for a 150 HP.

Some merchants offered both Mercury and Quicksilver branded products while others offered only one or the other.  These items are exactly the same (other than the branding) and the part numbers are similar with Quicksilver items often ending in Q01 and Mercury items ending in K01 (which, I believe, stands for Kiekhaefer – founder of Mercury).  In cases where both brands were offered, I chose the lower priced item.

In my comparison chart below, Quicksilver-branded items are denoted in blue text.  You can click on the chart to see a larger version.

Price Comparison for Mercury Supplies

As you can see by my shopping experience that was conducted in early October 2023, two merchants were considerably cheaper than all the rest – Leaders RPM and Boaters Emporium.  Boats.net would have been right there too if it wasn’t for the $14.95 shipping charge (they offer free shipping on orders of $149+).  Boaters Emporium actually had the lowest out-of-pocket cost overall because they were the only online merchant that did not apply sales tax (at least for me as a resident of Texas).

Yamaha Maintenance Items

For the Yamaha F150, I selected the Yamalube 10W-30 oil per the manufacturer’s recommendation.  Since the engine takes 4.8 quarts, I purchased one gallon and one quart.  I also selected the appropriate oil filter and two quarts of 80W-90 Gear Lube (since the lower unit requires 34 oz).

Below is a comparison chart of the prices for the Yamaha items as of early October, 2023.  Again, you can click on the chart to see a larger version.  Note that some of the merchants that carried Mercury products did not offer Yamaha (OEM) supplies.  These are denoted by NA in the chart.

One thing you might have noticed is that the total cost for the maintenance supplies for Yamaha is below that of the Mercury.  This is largely because of the need to purchase 2 gallons of oil for the Mercury vs. 1 gallon and 1 quart for Yamaha.  There is also less disparity in the total price across vendors that sell Yamaha products.

Of the seven online companies that carry Yamaha-branded products, Leaders RPM had the lowest total price ($95.24 with shipping) followed closely by Boats.net ($96.75) and PartsVu ($100.69).  And, with only an additional $10.75 purchase, the Leaders RPM order would have qualified for free shipping (since the $5.99 fee is waived with orders of $100+).  The purchase threshold to qualify for free shipping is a bit higher for Boats.net and PartsVu ($149+ for each).

There are a few specific things to note with two of the vendors.  For Leaders RPM, they no longer offer the Yamaha 10W-30 oil in the gallon size so I substituted 4 quarts instead (denoted by an “s” in the table above).  I also selected an alternative part number for the Gear Lube because they offer the same item with a gasket for a lessor price ($16.98 vs. $18.85).  The way I learned about this is that their site provides a “Recommended” list of items when you enter your desired part number.  This is a very useful feature – especially considering that they recommended a lower priced item in this case.

For Wholesale Marine, the Yamalube 10W-30 in the gallon size was listed as “Out of Stock” at the time of my analysis and so this was substituted with 4 quarts instead.

The Top 5 Places to Buy Engine Supplies

So with the above price comparisons as a key (but not the only) input, here are my top 5 recommended online merchants to buy engine supplies.

1. Leaders RPM

This is a family-owned business out of Kalamazoo, MI that has been in operation for over 40 years.  They have earned my top spot for several reasons:

  • They offer very competitive prices for both Mercury and Yamaha supplies.
  • They are an actual dealer and distributor/fulfillment center and so they carry many items in stock and can ship them quickly. In fact, orders received by 2 pm ET are shipped the same day.
  • They were the only dedicated marine supply company that performed 100% on both a “keyword” search and a “part number” search of the maintenance items. Only Amazon.com and Walmart.com were also able to do this.
  • Their business is an accredited, A+ business by the Better Business Bureau and they receive very high satisfaction ratings via Google (4.7 out of 5 based on 2,242 reviews)

Plus, their shipping policy is attractive ($5.99 flat rate for most items and free shipping on orders of $100+) and their return policy is very fair (90 days to return item if uninstalled, unused, unworn, in resalable condition and in the original packaging).

As an added bonus, they are currently offering $10 off a purchase of $110+ when you sign up for their newsletter.

2. Boats.net

Established in 1999, Boats.net is part of the Outdoor Network conglomerate and is based out of Albany, GA.  Like Leaders RPM, Boats.net offers very attractive prices for both Mercury and Yamaha supplies.  In fact, they even offer a price match guarantee on OEM items.  Besides their competitive prices, here are some other reasons why I ranked them #2:

  • They are an actual parts distributor which means they have greater control over the fulfillment process than a “drop shipper”. The benefit is you are more likely to get your items in a timely fashion and have greater recourse if something goes awry.
  • They offer free shipping on orders of $149+. However, this is not as generous as Leaders RPM (free shipping on orders $100+) and their price-match guarantee does not include shipping charges.
  • Their return policy is very fair (45 days) but only half that of Leaders RPM (90 days).
  • The website did poorly on keyword searches (only 17% of items correctly located) but did perfect (100%) on part number searches as did most every other online merchant evaluated.
  • They are an accredited, A+ business by the Better Business Bureau but have had 11 complaints in the past 3 years. Also, their customer satisfaction rating on Trust Pilot is decent but not outstanding  (3.7 out of 5 based on 366 reviews).

I suspect you are less likely to get a personal touch at Boats.net vs. a family-owned business like Leaders RPM.  However, this should not be a big issue on most orders (when you don’t need to interact with a representative).  They offer excellent prices (especially if you anticipate spending $149+ which qualifies for free shipping) and they seem to offer a broad selection.   Boats.net is definitely one to check out when shopping for your boating supplies.

3. PartsVu (Yamaha supplies)

PartsVu is a major parts distributor located in Naples, FL that was acquired by One Water Marine (major conglomeration of marine dealerships) in 2021.  They carry a wide selection of OEM and aftermarket parts and were rated third for the following reasons:

  • Their prices were fairly competitive on Yamaha items (3rd best out of the 7 that carried the Yamaha supplies) but no so with Mercury (8th out of 9).
  • Most items are fulfilled and shipped directly from their warehouse and so your order should be processed and items delivered in a timely basis in most cases.
  • The shipping (free on orders of $149+) and return policy (45 days for unused/undamaged items in original packaging) is similar to that of Boats.net.
  • Compared to other dedicated marine merchants, PartsVu did relatively well in terms of keyword searches (67% of items correctly located) and equally well in terms of part number searches (100%).
  • Their satisfaction rating via Google is equally strong as Leaders RPM (4.7 out of 5 based on 1,841 reviews). However, the company has received 17 complaints via the BBB in the past 3 years.

If you own a Yamaha and can’t get what you need at Leaders RPM or Boats.net, then PartsVu is worth a look.

3. Bass Pro Shops (Mercury supplies)

This major outdoor retail chain and distributor is also a licensed Mercury dealer and so they offer a wide selection of Mercury/Quicksilver products for their retail and online customers.  They receive my 4th ranking for the following reasons:

  • Their prices are good, but not the best, for Mercury items (but they don’t carry Yamaha items).
  • They have a large and sophisticated distribution center and should be able to fulfill most orders in a timely fashion.
  • If you happen to live near a Bass Pro Shops store, you can order items and pick them up in-store the same day if the item is in stock and the order placed by 4 pm ET Monday – Saturday or 2 pm ET on Sundays.
  • Their shipping policy is one of the best with free shipping on orders of $50+ and only $5 for orders below that.
  • The website was able to locate most items via a keyword search (67%). However, for part numbers, you need to enter the numbers in the format that Bass Pro expects.   Specifically, many Mercury/Quicksilver part numbers in my test begin with “92-“ or “35-“.  However, you have to remove these prefixes in order for Bass Pro to correctly locate the items.

If your order is fairly small, Bass Pro Shops might offer the lowest total cost because of their shipping policy.  They might also be a good choice if you have a Bass Pro Shops store near you and need the items the same day.

5. Amazon.com

The prices for the engine supplies at Amazon.com were not great but not outrageous either.  They made it to my top 5 simply because they could be a good option if you only need one or two items because they often offer free shipping.  Plus they have a reputation for processing and delivering orders quickly (especially if fulfilled by Amazon).

But this brings up an important topic.  Most of the marine products sold through Amazon (and Walmart.com) for my analysis involved an outside company.  You can typically see this under the “Add to Cart” button.  Here you will find one of three scenarios:

  • Sold and fulfilled by (company)
  • Sold by (company) and fulfilled by Amazon
  • Sold and fulfilled by Amazon

Of the ten separate items included in my analysis, three were handled via the first method (where the outside company sells and fulfills the item), four were handled the second way (where the company stores the products at an Amazon warehouse and Amazon fulfills), and three were handled the third way (Amazon sells and fulfills the item).

Knowing which approach is used can be important.  If it is the first method, then you are relying on that outside company to get you your items in a timely fashion.  And, any returns are handled by them – not Amazon.

Fortunately, because Amazon.com is the “800 lb Gorilla” of online retailers, most companies that work with them are largely compelled to provide quality and timely service.  Amazon even reports their performance record on their site which you can see by clicking on the “sold by” company name. Nonetheless, it might be a good idea to check out the outside company’s reputation with Amazon before you pull the trigger.

If it is either of the latter two methods, then Amazon is responsible for the fulfillment and handling of returns which provides a degree of assurance that your order will be handled quickly and professionally.

The bottom line is that if you just need a couple items or your purchase amount would not be sufficient to qualify for free shipping elsewhere, then ordering on Amazon.com might be your best option.

Companies that Didn’t Make the Cut

The following is a brief explanation for the remaining companies that did not make my top 5 list:


Walmart has adopted a similar business model as Amazon for their online store (partnering with outside companies to sell products) – they just don’t do it nearly as effectively.  The competitiveness of their prices depends on the outside companies they are affiliated with.  In my analysis, the prices for the Yamaha supplies were very competitive because most of these items were handled by Leaders RPM (my number 1 recommended source).  Unfortunately, this was not the case for the Mercury/Quicksilver items and the outside vendors that Walmart.com partnered with had prices that were consistently higher than all other online merchants evaluated.

Ironically, the Wal-Mart retail stores do offer very attractive prices on a variety of Quicksilver items based on my prior personal experience (although I did not shop their retail stores for this analysis).  But, the Wal-Mart retail business appears to be handled independently of their online shop.  The key point is that if you own a Mercury and have a store near you, shopping at Wal-Mart could be an excellent option for your marine engine supplies (I don’t know if they carry Yamaha items); just don’t waste your time shopping at their online store for your engine maintenance needs.

West Marine

This major marine retailer did not make the cut because their online prices for Mercury/Quicksilver items were not very competitive and they didn’t offer OEM items for Yamaha.  If you do happen to shop for parts there, be aware that you might need to remove the prefixes (e.g., 92- or 35-) from the Mercury/Quicksilver part numbers in order to correctly locate the desired items in your search (similar to the issue with Bass Pro Shops).


This Connecticut company has been around since 1938 and so they must certainly be doing something right in terms of providing good customer service.  They are a major seller/distributor of inflatable boats and “loose” (unrigged) outboard motors.  And, their prices for Yamaha supplies are actually quite good.  It is their high cost for shipping ($19.95 for the set of Yamaha items) that put them out of contention.  However, this fee would have been waived had the total order amount been slightly higher (since they offer free shipping on orders of $100+).  Therefore, if you own a Yamaha and anticipate spending $100+, then Defender is definitely worth a look and their prices should be comparable to that of my top 3 picks – Leaders RPM, Boats.net and PartsVu.

Boaters Emporium

On the surface, Boaters Emporium looks very attractive because they offer competitive prices (similar to Boats.net and Leaders RPM) on Mercury items,  they have an attractive shipping policy (free on orders $70+), and they don’t charge sales tax for most/all locations.  This means your net outlay would likely be cheaper than buying elsewhere.

However, on further inspection, I discovered that the business appears to be operating out of a New Jersey residence and the owner is relying on a network of drop shippers to handle the inventory and fulfillment duties.  This doesn’t mean that you will necessarily get unsatisfactory service but it adds a degree of risk.   In fact, when I searched for reviews online, I found that some were completely happy and others were not – and that is exactly my point.

So, if you are really focused on getting the lowest possible price (by avoiding sales tax) and don’t mind gambling a little bit, then Boaters Emporium might we worth a shot.

Wholesale Marine

Located in Cincinatti, OH, Wholesale Marine proudly states on their website that the company has been recognized by Newsweek as one of America’s Best Trending Online Shops for 2021.  Their shipping policy is very good (free shipping on orders of $99+, $6.99 for orders below that) and their return policy is equally generous as Leaders RPM (90 days of receipt).  However, their current prices are simply not that competitive and so there is no compelling reason to shop there instead of one of my top 3.


Even though I have been involved in the marine industry for over three decades and have personally owned boats most of my adult life, I had never heard of Leaders RPM prior to this in-depth analysis.  Now they will be my go-to source and where I recommend you shop based on what I learned through this investigation.  But you should also check out Boats.net and perhaps even PartsVu (especially if you are a Yamaha owner) for a price comparison.

However, before you begin your shopping journey, one key piece of advice is to first look up the exact part numbers for each of the items you need (and keep in a folder or electronic file for future reference).  This will save you considerable time and frustration with the shopping process since most sites don’t do a very good job with “keyword” searches.

If you have done business with any of the companies listed above or know of other online merchants that provide good prices and excellent service, please share your experience in the comments section below.

Jerry Mona - BoaterInput

About the author

Jerry Mona is an avid boater and angler and long-time boating industry insider. With over three decades of experience, he is often considered to be the leading research expert with boaters and has helped numerous manufacturers and trade associations to understand the needs, wants, attitudes and behaviors of boaters. He now shares many of his insights about boats and boaters for free on his BoaterInput.com website.

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