If your Ryobi CS30 weed trimmer fails to start, you must troubleshoot the engine. The engine is a small two-stoke engine, which requires the user to pre-mix the engine oil into the gasoline. Several things could cause a small two-stroke engine to fail starting when you pull on the pull string. Take a logical approach to troubleshooting and you will save money and get the trimmer working in a quicker manner.
Remove the gas cap and check the gas container to ensure it has fuel in it. If it is empty, fill it up and attempt to start the trimmer. If it is fill or still does not start, proceed to the next step.
Disconnect the spark plug wire from the spark plug and then remove the spark plug with a socket and ratchet. Inspect the tip of the spark plug that goes into the engine. If the tip is black and covered in oil, you likely fouled out the plug. Lightly sand the diodes on the plug to remove oil and then reinsert the plug and reconnect the spark plug wire.
Press the primer bulb on the carburettor seven times. Place the start lever onto the "Start" position and pull the starter until the engine starts. If the engine does not start within seven to ten attempts, move on to the next step.
Drain the gasoline from the gas tank. To do this, remove the lid and hold the tank upside down over a gas can.
Inspect the fuel line that extends from the gas tank to the carburettor for a clog. To do this, loosen the hose clamps with a screwdriver. Blow air into the end of the hose. If the air flows freely, the hose is fine. If the air restricts, remove the blockage with a screwdriver shaft. Place the gas line back onto the trimmer.
Mix 87-octaine fuel with two-stroke engine oil. Add 76.9ml of oil per gallon and thoroughly mix. Fill the gas tank up and place the lid back on the tank.
Remove the spark plug again and clean it. Place the spark plug back into the motor and attempt to start the mower. If it does not start within seven to ten attempts move to the next step.
Replace the spark plug and the spark plug wire. If it still fails consult a Ryobi authorised repair centre to set up a claim for repair.