Small Engine Starts Then Dies
In This Guide
An engine that fires up for a few seconds then quits is telling you something specific. When a small engine starts then dies, it usually means fuel gets in to start it but cannot keep flowing. This guide covers the common causes in order, so you can find the blockage and get running again.
Why It Starts Then Quits
The pattern is the clue. There is just enough fuel sitting in the carburetor bowl to fire the engine, but the supply behind it is blocked, so the bowl empties and the engine dies.
That points almost every time to the carburetor or the fuel supply, not to spark.
The Usual Causes
- Clogged carburetor jet. Varnish from old fuel blocks the tiny idle or main passage.
- Blocked fuel cap vent. The tank cannot draw air, so a vacuum forms and starves the engine.
- Stuck choke. A choke left partly closed floods the engine after it warms.
- Dirty air filter. Starves the engine of air once it is running.
- Stale fuel. Will fire briefly but cannot sustain combustion.
Quick Test for the Fuel Cap
This one takes ten seconds and rules out a common cause. Start the engine, and the moment it begins to die, loosen the fuel cap. If it keeps running with the cap loose, the cap vent is blocked and needs cleaning or replacing.
The Real Fix
If the cap test does not solve it, the carburetor is the likely cause. Cleaning the jets clears the varnish that starves the engine. Follow the carburetor cleaning guide step by step.
For mowers, the mower version of this fault has model specific tips.
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