When and why you need a new carburetor
A Briggs and Stratton carburetor may need replacement when the engine won't start, runs rough, stalls frequently, or won't stay running at idle. These symptoms often mean the carburetor is clogged with old fuel residue, has a cracked gasket, or has internal parts that have worn out. Before you replace it, try cleaning the carburetor first — soaking the jets and passages in carburetor cleaner sometimes fixes the problem without buying a new part.
If cleaning doesn't work, or if you see visible cracks in the plastic body or metal casting, replacement is your next step. A new carburetor costs between $40 and $150 depending on your engine model, and the job itself takes one to three hours if you have basic tools and follow the steps in order.
Key Takeaways
- You will need your engine's model and spec number to order the correct carburetor — this number is stamped on the engine block and appears on your original receipt or manual.
- Drain the fuel tank completely before you start, because fuel will spill when you disconnect the fuel line.
- Take a photo of the linkage and springs before you remove them, so you can reconnect them in the same position on the new carburetor.
- The new carburetor comes with a gasket kit; do not reuse the old gasket, because a leak will cause the same problems you just fixed.
Finding the right replacement carburetor for your engine
Briggs and Stratton makes different carburetors for different engine sizes and types. The wrong carburetor will not fit, or will fit but run poorly. Find your engine's model and spec number on the metal plate bolted to the engine block — it looks like a small rectangular label with numbers stamped or printed on it. Write down the full number.
Go to the Briggs and Stratton parts website or call a local small-engine dealer with that number. They will tell you the exact carburetor part number you need. You can also check your engine's manual if you have it. Order the carburetor with its gasket kit included — most retailers sell them as a set. Expect to pay $50 to $120 for the carburetor and gasket kit combined.
Preparing your engine and workspace
Work in a well-lit area with the engine cold. Drain the fuel tank by either running the engine until it stops, or by using a fuel siphon to pull the gas out into a safe container. Do not skip this step — fuel will pour out when you disconnect the fuel line, and you do not want gasoline on your work surface or clothes.
Gather your tools: a socket set or wrench set, a screwdriver (usually Phillips head), needle-nose pliers, and a clean rag. Have the new carburetor and gasket kit ready. Take a clear photo of the fuel line, throttle linkage, and any springs connected to the old carburetor before you touch anything — this photo will guide you when you install the new one.
Removing the old carburetor
Locate the fuel line running from the tank to the carburetor. Loosen the clamp holding it with pliers or a screwdriver, then gently pull the line off the fuel inlet nipple. A small amount of fuel may drip out even after draining — have a rag ready.
Disconnect the throttle cable or linkage by unbolting or unclipping it from the carburetor. If there are springs attached, remove them carefully and set them aside in order. Unbolt the carburetor from the engine block — usually two or four bolts — and lift it straight up and away. Do not force it; if it sticks, rock it gently side to side.
Scrape off the old gasket from the engine block using a plastic scraper or old credit card. Do not use a metal tool, which can gouge the mounting surface. Wipe the area clean with a dry rag so the new gasket will seal properly.
Installing the new carburetor
Place the new gasket on the engine block, aligning the bolt holes. Set the new carburetor on top of the gasket and insert the bolts. Tighten them in a crisscross pattern — tighten one bolt a little, then the opposite bolt a little, then repeat — so the carburetor sits evenly. Do not over-tighten; snug is enough.
Reconnect the fuel line by pushing it onto the fuel inlet nipple until it seats, then tighten the clamp. Reconnect the throttle linkage and springs in the same position shown in your photo. If your engine has a choke cable, reconnect that as well. Double-check that all connections are tight and nothing is pinched or twisted.
Starting and adjusting the new carburetor
Fill the fuel tank with fresh gasoline. Prime the carburetor by pressing the primer bulb (if your engine has one) several times until fuel flows. Turn the key or pull the starter cord. The engine should start within a few pulls. If it does not, check that the fuel line is connected and the choke is in the correct position for a cold start.
Once the engine runs, let it warm up for a minute. It may run rough at first while old fuel clears the lines. If it continues to run rough or stalls at idle after warming up, the carburetor may need adjustment. Most Briggs and Stratton carburetors have idle speed and fuel mixture screws on the side. Refer to your engine manual for the correct adjustment procedure, as turning these screws incorrectly can make the problem worse.
Troubleshooting after replacement
If the engine still won't start after you install the new carburetor, check that fuel is reaching the carburetor by disconnecting the fuel line at the carburetor inlet and turning the key — fuel should flow out. If no fuel flows, the fuel pump or tank valve may be blocked. If fuel flows but the engine won't start, the spark plug may be fouled; remove it and inspect for black buildup or wetness.
If the engine starts but runs very rough or stalls, air may be trapped in the fuel line. Loosen the fuel line at the carburetor inlet slightly and turn the key until fuel flows out without bubbles, then tighten it again. If the engine still runs poorly, the carburetor may not be seated evenly on the gasket — remove it, check that the gasket is not torn or folded, and reinstall it.
Frequently Asked Questions
Do I need to drain the fuel tank before I start?
Yes. Fuel will spill when you disconnect the fuel line, and old fuel left in the tank can gum up your new carburetor. Drain it completely by running the engine until it stops, or use a fuel siphon to pull the gas into a container.
Can I reuse the old gasket?
No. Old gaskets lose their seal and will leak, causing the same running problems you are trying to fix. The new carburetor comes with a fresh gasket kit — use it.
What if the new carburetor leaks fuel?
Check that the fuel line clamp is tight and the line is fully seated on the inlet nipple. If it still leaks, the gasket may not be sealing evenly. Remove the carburetor, inspect the gasket for tears or folds, and reinstall it, tightening the bolts in a crisscross pattern.
How do I know which carburetor to order?
Find your engine's model and spec number on the metal plate bolted to the engine block. Call a Briggs and Stratton dealer or visit their parts website with that number, and they will give you the correct part number. Do not guess — the wrong carburetor will not fit or will run poorly.
Should I adjust the fuel mixture screws on the new carburetor?
Most new carburetors come pre-set from the factory and do not need adjustment. If the engine runs rough after warming up, refer to your engine manual for the correct idle speed and fuel mixture settings before turning any screws.