Where Do I Find My Boat Engine Serial Numbers?

Every marine engine has a serial number that should be easily identifiable on the engine. In some cases they can be corroded off or hard to read, or the sticker is missing. With all the different makes and models it can be confusing to know where to look.

We’ve started and list with pictures of locations and will update as time goes on. We will include where to find your marine engine serial number for the following engines:

Petrol Inboards


Petrol Outboards

Petrol Generators

Diesel Generators

The serial numbers in all our pictures below have been blurred intentionally.

Petrol Inboards


There are a number of different locations you might find a Mercruiser engine serial number. These different locations are:

  1. On the stickers on the sides of the plastic cowling.
  2. Above the starter motor near the bellhousing.
  3. On the starboard side of the engine block, near the welsh plugs (if the engine has been replaced and has a remanufactured block).
  4. On the sticker on the heat exchanger (if it has a heat exchanger fitted).

You might find that on many model of boats, it’s best to get your phone on camera mode, with flash enabled, to identify the serial number. Engines are installed with tight tolerances and as a result, often don’t provide easy access to the side of the engine.

Mercruiser 4.3L serial number locations

Volvo Penta

The Volvo Penta petrol engines have the serial number located on the plastic cowling on top of the engine.


The Crusader Inboard serial numbers are usually located on a plaque on the starboard side of the sump.



Newer Cummins QSM/QSC model engines typically have a sticker fitted to the rocker cover. Older model Cummins (6BTA for instance) have a serial plaque fitted to the port side of the timing cover.


You will often find Caterpillar marine diesel serial numbers on the top of the rocker cover in the form of a small sticker.

Volvo Penta

These are typically located on the sticker on top of the plastic cowling, and a plaque on the port side near the sump line.


Looking for a Yanmar serial number? It’ll like be located on the top of the engine on a plaque, or on the cylinder head.


You’ll usually find Steyr diesel serial numbers on top of the engine near the emission control information sticker.


MAN marine diesel serial numbers are usually found on the port side of engine block, below exhaust manifold near engine mount. They are a black metal plaque attached to the engine.

Petrol Outboards


Locating the serial number on outboards is usually simple. On a Mercury outboard, you’ll usually have the serial number located on the starboard side of the swivel bracket, the mounting bracket or the cylinder head in sticker form.

Evinrude eTec

Another easy find – Evinrude eTec serial numbers are located on the port side of swivel bracket.


The Honda outboard serial numbers are usually found on the port side of the trim bracket.


You will typically find the Yamaha outboard serial numbers on the port side of the trim bracket.


Not sure where to find the serial number on a Suzuki outboard? It’s usually on the starboard side of the trim bracket.


For the most part, you’ll find Johnson outboard serial numbers on the port side of the trim bracket.

Petrol Generators


The Kohler generator serial numbers are usually found on top of electrical box.

Diesel Generators


The serial numbers on Onan generators are usually located on the port side of the front casing. On older model they can be found on top of the electrical box, or near the electrical windings in sticker form.

Your engine serial number will likely need to be identified when purchasing a boat, or ordering parts. I hope this article has helped you speed up the process of finding the serial.

Having trouble finding the serial number or would like the condition of the engine inspected? We can assist with a Pre-Purchase Survey and Mechanical Inspection in Sydney and Gold Coast region.

Are we missing a manufacturer’s serial number location? Feel free to email through with location and pictures to info@boatbuy.com.au.

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