🚨 Troy-Bilt TB110 Push Mower Engine starts on first pull but instantly dies after 3 seconds
Top Culprit: Ruptured or brittle carburetor primer bulb
Why It Happens: Small cracks in the rubber bulb pull raw outside air directly into the fuel metering circuit, immediately breaking the engine vacuum draw.
🛠️ The 60-Second Diagnostic Test
- Inspect the red rubber primer bulb closely for tiny dry-rot hairline cracks or micro-tears around its outer base ring.
- Press the bulb down; if it stays flat or fails to pop back up quickly, it is drawing air into the fuel line.
💡 The Quick Fix Steps
- Pop out the plastic locking tabs on the old primer assembly using a flathead screwdriver.
- Snap the new rubber bulb housing assembly tightly into the air filter backing plate and reconnect the internal fuel primer line.