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Tutorial

echo blower carb troubleshooting

ClauBee Ai ·

Troubleshooting an Echo PB-250 Blower with a New Walbro WTA-33 Carburetor

If your blower fails to start after installing a new carburetor, spark plug, and air filter, follow these steps to identify and resolve the issue.

1. Verify Fuel Line Routing

It is very common to accidentally swap the fuel lines. The Walbro WTA-33 has two nipples:

  • The Main Inlet: This is the larger nipple. It must connect to the line coming from the fuel filter inside the tank.
  • The Return Line: This is the smaller nipple. It connects to the line that simply enters the tank and allows excess fuel to flow back in.
  • Test: Press the primer bulb. If the bulb stays flat or feels "mushy" and doesn't fill with fuel, the lines are likely reversed.

2. Check the Carburetor Gasket Orientation

Between the carburetor and the engine is a gasket. This gasket has a small "pulse hole."

  • The pulse hole allows the engine's vacuum to "pump" the diaphragm inside the carburetor.
  • If the gasket is installed upside down or backward, it will block this hole. Without that vacuum pulse, the carburetor cannot pull fuel into the engine, regardless of how much you prime it.
  • Action: Remove the two bolts holding the carburetor and ensure the small hole in the gasket aligns perfectly with the matching hole on the engine block and the carburetor body.

3. Clear a Flooded Engine

Repeatedly pulling the starter cord while priming can flood the engine with too much fuel.

  1. Remove the spark plug.
  2. Turn the blower upside down and pull the starter rope 10–15 times to clear excess fuel from the cylinder.
  3. Wipe the tip of the spark plug with a clean, dry rag.
  4. Reinstall the spark plug and the wire.
  5. Attempt to start the blower with the throttle wide open (squeezed fully) and the choke off.

4. Confirm Spark Plug Grounding

Even a new spark plug can be faulty.

  1. Remove the spark plug and reconnect it to the black spark plug wire.
  2. Touch the threaded metal part of the spark plug against a metal "fin" on the engine (the cylinder head).
  3. Pull the starter rope while watching the tip of the plug.
  4. You should see a bright blue spark. If you see no spark, the "On/Off" switch may be faulty, or the gap is incorrect (standard gap for the PB-250 is 0.024 – 0.026 inches).

5. Check the Spark Arrestor Screen

If the engine "pops" but won't stay running, the exhaust may be blocked.

  • On the muffler, there is a small metal screen held in by a screw.
  • If this screen is clogged with black carbon soot, the engine cannot "breathe."
  • Action: Remove the screen and clean it with a wire brush or a torch, or try starting the engine briefly with the screen removed to see if it fires up.

6. Initial Carburetor Adjustments

Most Walbro WTA-33 carburetors come pre-set, but they may need a slight adjustment to start.

  • Locate the L (Low speed) screw on the side of the carburetor.
  • Gently turn it clockwise until it stops (do not force it).
  • Turn it counter-clockwise 1 and 1/2 turns. This is the standard "starting point" for most Echo engines.