engine starts fine but then dies after about 30 seconds, like it’s running out of gas

Diagnosis

The symptoms you are describing—starting normally but stalling after 30 seconds—indicate a vacuum lock or a fuel starvation issue. When the engine starts, it consumes the small amount of fuel already sitting in the carburetor's float bowl. Once that initial reservoir is depleted, the engine relies on a constant flow of fresh gasoline from the tank. If the fuel cannot flow, the engine starves and dies, mimicking the behavior of an empty tank. This is most commonly caused by a failure in the fuel tank vent. As fuel leaves the tank, air must enter to replace it; otherwise, a vacuum forms inside the tank that eventually becomes stronger than the gravity feed, pulling the fuel back and stopping the flow. Alternatively, the main jet (the tiny orifice inside the carburetor) may be partially obstructed by "varnish"—a sticky residue left behind by ethanol-blended fuels—which allows enough fuel through for a cold start but not enough to maintain a steady combustion cycle under load. You can confirm a vacuum lock by attempting to start the engine with the gas cap completely removed; if it runs indefinitely, the cap vent is the culprit.

How to Fix It

Follow these steps to resolve the fuel delivery failure on your Briggs & Stratton S2200:

1. Test for Vacuum Lock: Remove the fuel cap entirely and pull the starter cord. If the engine runs for several minutes without stalling, the vent in the gas cap is clogged. Use a thin piece of flexible wire or a needle to clear the small breather hole in the cap, or replace the cap entirely.
2. Drain the Float Bowl: Locate the yellow or brass drain screw at the very bottom of the carburetor bowl. Place a small container underneath and loosen the screw. Allow all fuel to drain out; this removes any water or sediment that has settled at the bottom of the bowl. Tighten the screw back firmly.
3. Clean the Main Jet: Remove the bolt holding the carburetor bowl in place. Carefully drop the bowl off. Look up into the center tube (the emulsion tube) where the bowl was attached. Use a thin piece of copper wire (stripped from an electrical cord) or a specialized carburetor cleaning needle to poke through the tiny hole at the bottom of the jet. This clears the varnish blockage.
4. Clear the Fuel Line: Disconnect the fuel line from the carburetor inlet. Place the hose into a clean jar and tip the pressure washer slightly. If the fuel glugs or flows slowly, there is a restriction in the line or a clogged fuel filter. Replace the line if it feels stiff or cracked.
5. Reassemble and Prime: Reinstall the bowl and cap. Press the primer bulb 3 times firmly to force fuel into the throat of the carburetor and restart the unit.

If That Didn't Work

• Check for "Gas-Lock" in the Tank: If you have a fuel shut-off valve, ensure it is fully turned to the 'On' position. Sometimes the valve handle feels turned, but the internal gate is stuck halfway, restricting flow enough to cause a stall after the bowl empties.
• Inspect the Air Filter: A severely oil-soaked air filter can restrict airflow to the point where the engine runs "rich," causing it to flood and stall shortly after starting. Remove the filter element; if it is black or dripping with oil, replace it immediately.
• Inspect the Spark Arrestor: Remove the small metal screen (spark arrestor) from the exhaust muffler using a socket wrench. If the screen is clogged with carbon soot, back-pressure builds up in the cylinder, which can cause the engine to choke out and die after it reaches operating temperature. Clean it with a wire brush or a torch.
• Verify Fuel Quality: If the gas has been sitting for more than 30 days, the octane level drops and the fuel begins to separate. Drain the entire tank and refill with fresh, stabilized 87-octane gasoline.

Heads Up

• Avoid Ethanol: Use ethanol-free gas or a high-quality fuel stabilizer (like STA-BIL) to prevent the gummy deposits that clog the S2200's small carburetor jets.
• Oil Level Warning: Ensure the oil is topped off. Some Briggs & Stratton engines have a low-oil shutdown sensor that can trigger as the engine vibrates or tilts slightly during operation, causing an abrupt stall.
• Correct Priming: Over-priming can flood the engine. If it starts hard but dies quickly, try starting it with only one prime pulse instead of three.
• Storage Prep: Always run the engine until the tank is completely dry before storing the unit for the winter to prevent the carburetor from gumming up.