Mercury Part Number Superseded: What Does That Mean?

You search for a Mercury part number from an old manual, parts diagram, or the part you just removed from your engine, only to find a completely different number listed as the replacement.

The original part may show as superseded, SST, replaced by, or no longer available under that number.

That doesn't necessarily mean the part is discontinued.

In many cases, Mercury has simply replaced the old part number with a newer OEM part number. Understanding superseded Mercury part numbers can make finding parts for older Mercury outboards and MerCruiser engines much easier.

What Does "Superseded" Mean for a Mercury Part?

A superseded part number is an older part number that has been replaced by a newer number in the manufacturer's parts system.

For example:

Old Mercury Part Number → New Mercury Part Number

If Mercury identifies the new number as the replacement for the old one, you would normally order the current superseding part number rather than continue searching for the original number.

The old number is still useful, though. It creates a trail back to the original application and is often exactly what an owner or technician searches when trying to identify a replacement.

Why Does Mercury Change Part Numbers?

A Mercury or Quicksilver part number can change for several reasons.

Sometimes the component itself has been updated. There may be a design revision, material change, manufacturing update, or another change to the current replacement.

Other times, the change may involve how the part is supplied. An individual component might become part of an updated assembly or kit, for example.

There can also be multiple supersessions over the life of a part.

That can look something like:

Original Number → Replacement Number → Newer Replacement Number → Current Part Number

This is particularly important with older Mercury and MerCruiser engines that have been supported for many years.

Does a New Part Number Mean It's a Different Part?

Not necessarily.

A superseding part may look nearly identical to the original, or Mercury may have made noticeable changes to it.

The important part is whether Mercury identifies the newer number as the correct replacement for the original application.

This is why we don't recommend deciding that two Mercury parts are interchangeable simply because they look the same.

A small difference in a gasket, connector, mounting point, internal component, calibration, or kit contents can matter even when two parts look almost identical in photos.

Why Searching the Old Mercury Part Number Still Matters

Don't throw away the old number just because it has been superseded.

Older Mercury part numbers are extremely useful when researching parts.

You may find an old number:

• Stamped or printed on the original component
• In an older Mercury parts diagram
• In a service manual
• On old packaging
• On an invoice from a previous repair
• In an online discussion or older parts listing

Searching that exact number can help trace the part to its current Mercury replacement number.

That's also why you'll sometimes see several numbers listed on Gregor's Marine product pages. When we can verify that an older Mercury number has been superseded, we include it so someone searching the number they already have can still find the current part.

Superseded Is Not the Same as Discontinued

This is an important distinction.

Superseded generally means there is a newer part number replacing the old one.

Discontinued or no longer available can mean Mercury no longer supplies that part, particularly if no current replacement is listed.

So if you search an old Mercury part number and can't find it for sale, don't immediately assume the part is unavailable.

There may be a newer number you should be searching instead.

Can a Mercury Part Have More Than One Old Number?

Yes.

A current Mercury Precision Parts or Quicksilver component can sometimes replace several previous part numbers.

This is one reason part-number research gets confusing. You might find three different numbers online that appear to describe the same component, while Mercury's current catalog shows a fourth number.

The newest number in a verified supersession chain is generally the one you want to work from when ordering.

What About Numbers With Different Prefixes or Suffixes?

Mercury part numbers have appeared in different formats over the years, and older numbers may include prefixes or suffixes that aren't present on the current replacement.

Newer Mercury part numbers also frequently use the 8M format.

Don't assume two numbers refer to different applications just because their formats look completely different. At the same time, don't assume a similar-looking number is automatically interchangeable.

The supersession needs to be verified.

Your Engine Serial Number Still Matters

Finding a superseded number answers one question:

What replaced this old part number?

It doesn't always answer another important question:

Is this the correct part for my specific engine?

Mercury parts can vary by engine family, production range, configuration, and other factors. This is especially important for components such as ECMs, fuel-system parts, electrical components, gearcases, water-pump parts, trim components, and MerCruiser drive parts.

That's why the engine or drive serial number should still be used to confirm compatibility.

Need Help Finding an Old Mercury Part Number?

Gregor's Marine has been working with Mercury engines and OEM parts for more than 40 years.

If you have an old Mercury, Mariner, Quicksilver, or MerCruiser part number, our team can help determine whether it has been superseded and identify the current replacement when one is available.

When contacting us, send the part number you have along with your engine or drive serial number. Photos of the original component can also be helpful when identification is unclear.

Call Gregor's Marine at 727-596-5929 for Mercury OEM parts assistance.

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FAQs

Can I still use an old Mercury part number to search for a part?

Yes. An old number can be extremely useful for identifying the current replacement, even if Mercury no longer sells the part under the original number.

Does superseded mean the old Mercury part is bad?

No. Supersession does not automatically mean there was a problem with the original part. Part numbers can change for many reasons.

Is a superseded Mercury part guaranteed to fit my engine?

The supersession tells you which part replaced an older number, but your engine or drive serial number should still be used to verify the application before ordering.

What if my Mercury part number has been discontinued with no replacement?

Some older components eventually become unavailable from Mercury. In those cases, availability may depend on remaining new-old-stock inventory, another approved replacement, or repair options for the particular component.