Where Is The Part Number On A Chainsaw Carburetor: Guide

Usually stamped or laser-etched on the carb body, near the mounting flange.

If you’ve ever squinted at a carb and still wondered where is the part number on a chainsaw carburetor, you’re in the right place. I’ve rebuilt hundreds of saws in the field and on the bench, and I’ll show you clear, repeatable ways to find, read, and use that tiny code with confidence. This guide covers locations by brand, how to decode markings, and what to do if the number is gone or unreadable.

Why the part number matters and what it looks like

The part number tells you the exact carb model. It helps you order the right rebuild kit, metering diaphragm, needle, and gaskets. It also helps you cross-reference for OEM or quality aftermarket parts.

You will often see a brand prefix plus a family code. Examples include Walbro WT-###, Zama C1Q-###, or Tillotson HU-###. Some carbs add a suffix for small revisions.

If you ask where is the part number on a chainsaw carburetor, it is almost always on the metal body or on a screwed-on plate. The code is stamped, etched, or inked. Look for clean, flat areas with good contrast.

Common places to find the number on the carb

You can find the marking in a few repeat spots. Use a flashlight and a small brush.

• Throttle side body. Look at the flat face near the throttle shaft.
• Mounting flange. Check the intake side or the air-filter side flange.
• Fuel inlet boss. Scan the raised block where the fuel line connects.
• Choke horn or venturi wall. Peek around the air intake mouth.
• Metering cover plate. Inspect the plate held by four screws on many carbs.
• Primer port area. Some have small laser text near the purge line nipples.

If you need a one-line guide to where is the part number on a chainsaw carburetor, start at the throttle body and the metering cover, then work around the flanges.

Brand-specific locations and tells

Different makers are fairly consistent. Here is how I track them during service.

Walbro

Walbro numbers like WT-, WTA-, WTE-, or HD- are stamped or etched on the carb body. Check the throttle side, the metering cover, or a flat boss near the fuel inlet.

Zama

Zama codes start with C1Q, C1M, C3A, etc. Look along the throttle body edge, the metering cover, or the air horn. Zama often laser-etches fine text, so tilt the carb in the light.

Tillotson

Tillotson marks HU, HS, or HL families. The stamp sits on the main body or along a flange surface. Some older units use deeper impressions that collect grime.

Ruixing, Hualong, Nikki, and clones

Many clone carbs print ink on the metering plate or body. The ink can wipe off. If you cannot read it, match by body shape and bolt pattern.

For anyone still asking where is the part number on a chainsaw carburetor by make, use these brand tells first. Then confirm with your saw’s illustrated parts list.

Step-by-step: Find and read the marking fast

Use this simple routine. It works at the bench or in the field.

1. Remove the air filter and the top cover. Photograph hose routing.
2. Wipe the carb with a dry brush. Use carb-safe cleaner on a rag, not a spray blast.
3. Shine a bright light along the throttle body and both flanges.
4. Rotate the carb and inspect the metering cover and primer ports.
5. Read the code out loud. Take a photo. Note any suffix letters or numbers.
6. Compare what you see to the parts list for your exact saw model.

This method is my go-to when someone asks where is the part number on a chainsaw carburetor during a quick diagnosis call. It keeps you from missing tiny laser marks.

Real-world examples and decoding tips

Here are patterns I see most in the shop. Use them to decode what you find.

• Walbro WT-215 or WT-891. WT shows the family. The digits set the exact kit.
• Zama C1Q-S173 or C1M-K77. The family is C1Q or C1M. The suffix marks a build.
• Tillotson HU-40 or HS-254. HU and HS are common in classic saws.

Watch for non-part markings. Casting codes, date dots, or QC stamps are not the part number. If in doubt, compare to the service manual and the rebuild kit index.

If you are still wondering where is the part number on a chainsaw carburetor after cleaning, check the metering cover edge and the intake flange one more time at a sharp angle. Fine laser text can hide until the light hits just right.

When the number is missing or unreadable

Sometimes the marking is gone. Ink fades. Bodies corrode. Do this instead.

• Use the saw’s model tag. Cross-reference the carb used for that serial range.
• Match the carb family by shape. Check bolt spacing, throttle shaft style, choke lever, and primer ports.
• Measure the venturi and flange. A caliper plus photos helps dealers match parts.
• Pull the old kit. The needle lever and diaphragm style can reveal the family.
• Compare photos in trusted parts catalogs. Look for screw count and plate shape.

If a customer asks where is the part number on a chainsaw carburetor and there is none to read, I match by body layout and then verify with the kit number table. It is slow, but it works.

Mistakes to avoid and pro tips

These small moves save time and money.

• Do not sand the body to “find” the stamp. You may erase it.
• Do not assume model equals carb. Mid-year runs can change suppliers.
• Clean before you read. Oil film hides laser text.
• Photograph everything. A clear, lit photo beats a smudged note.
• Verify kit fit by needle lever and diaphragm shape, not only by number.

My field tip: a headlamp plus a white index card makes marks pop. Angle the card to bounce light across the surface. This trick often ends the where is the part number on a chainsaw carburetor search in seconds.

Frequently Asked Questions of where is the part number on a chainsaw carburetor

Where is the part number on a chainsaw carburetor for Stihl saws?

Most Stihl carbs use Zama or Walbro. Check the throttle body edge, the metering cover, and the intake flange for laser-etched codes.

Where is the part number on a chainsaw carburetor for Husqvarna models?

Look on the carb body near the throttle shaft and on the metering cover plate. Many Husqvarna units use Zama or Walbro formats like C1Q- or WT-.

My carb only shows a brand code, not digits. What do I do?

Rotate the carb and check all flat faces for the full code. If only the family is visible, use the saw model’s parts list to narrow the exact variant.

Are casting numbers the same as the part number?

No. Casting numbers and date codes are not the service part number. The serviceable number is the brand-family code like WT-### or C1Q-###.

Can I order a kit without the part number?

Yes, but confirm fit by body shape, bolt spacing, and diaphragm style. Photos, caliper measurements, and the saw’s illustrated parts list help a lot.

Conclusion

Finding the carb code is simple when you know where to look and how to light it. Start with the throttle body, flanges, and metering cover, then cross-check it against your saw’s parts list. Use photos, clean surfaces, and brand patterns to speed the job.

Act now: grab a light, clean the carb, and note the full code before ordering parts. If you found this guide useful, subscribe for more hands-on small engine tips or drop a question in the comments.