How to fix your Echo gas leaf blower when it smokes
Mixing too much 2-cycle oil with the gas can cause excessive smoke from the leaf blower's engine; follow the guidelines in your owner's manual for mixing the fuel and 2-cycle oil. Most leaf blower engines use a 40:1 ratio of gas to 2-cycle oil. To achieve that mix, add a 3.2-oz bottle of 2-cycle engine oil to 1 gallon of gas.
A dirty air filter also can lead to engine smoke. If the filter prevents the carburetor from getting enough air to create the right fuel/air mixture. A fuel-rich mixture can cause the engine to smoke. Clean the air filter and perform preventive maintenance on the leaf blower to help prevent engine smoking.
Clogged jets inside the carburetor also cause excessive smoking because the carburetor can't mix the right amount of air with fuel. If the engine still smokes after completing preventive maintenance (which includes cleaning the air filter), you may need to rebuild or replace the leaf blower's carburetor.
How to troubleshoot your Echo gas leaf blower when it won't start
Your leaf blower engine needs gas, compression and spark. First, make sure there's fresh gas in the tank--old gas accumulates water and burns poorly. Replace the fuel if it’s old. Add fuel stabilizer to the gas when you refill the tank to help keep the fuel fresh.
If the fuel is fresh, complete the preventive maintenance on the air filter to make sure the carburetor gets air to mix with the fuel to start the engine. Follow the instructions for in your owner’s manual for cleaning and maintaining the air filter. Lightly coat the air filter with oil on some leaf blower models so the right amount of clean air enters the carburetor.
If the air filter is okay, check the fuel lines for cracks. Air enters the carburetor instead of fuel when fuel lines have cracks. Although the carburetor needs air through the filter, the carburetor doesn’t need air flowing through the fuel lines. Replace the fuel lines if you find cracks in the tubing.
If the fuel lines are okay but fuel doesn’t move through the lines when you press the primer bulb, the fuel filter may be clogged. Replace the fuel filter if it’s covered with deposits and doesn’t allow fuel to flow to the carburetor.
If fuel flows to the carburetor, remove the spark plug and see if the tip of the plug is wet (indicating the cylinder is getting fuel). If the cylinder isn’t getting fuel because of a clogged carburetor jet, rebuild or replace the carburetor.
If you see deposits or corrosion on the spark plug electrode when you pull it out, replace the spark plug.
Finally, to check for compression, remove the spark plug, press your thumb over the opening and pull the starter cord. If you don’t feel air pushing out from the cylinder, it’s likely that the piston rings need to be replaced. (For an accurate compression reading, use a compression gauge.)
A damaged recoil starter can also prevent you from starting the leaf blower engine. If you can’t pull the recoil starter rope, check the recoil starter and replace it if damaged.