Quick Answer
Your generator won't start after filling it with fresh fuel due to a combination of issues, including stale fuel in the tank, poor fuel flow, bad spark plug, faulty ignition coil, or weak battery.
Fuel System Checks
Before diving deeper, inspect your generator’s fuel tank. If it’s been sitting for a while, there might be stale fuel at the bottom that’s preventing the fresh fuel from flowing through. Check the fuel filter and replace it if it’s clogged or dirty. Make sure the fuel tank is at least 1/4 full to ensure adequate fuel flow to the carburetor. A good rule of thumb is to drain the tank and refill it with fresh fuel if it’s been stored for more than 30 days.
Spark Plug Testing and Replacement
A bad spark plug is a common culprit when it comes to generator starting failures. Remove the spark plug and inspect it for signs of wear or fouling. Use a spark tester to check for spark, and if it’s weak or absent, replace the spark plug with a new one. Make sure to gap the new spark plug to the manufacturer’s specifications, which is usually around 0.028-0.032 inches.
Battery Health and Ignition Coil Testing
A weak or dead battery can also prevent your generator from starting. Check the battery’s voltage level using a multimeter, and if it’s below 12.4 volts, charge or replace the battery. If the battery is healthy, check the ignition coil for signs of wear or damage. Use a multimeter to check the ignition coil’s resistance, which should be around 1-2 ohms for most generators. If the resistance is high or the coil is damaged, replace it. Finally, clean the carburetor by removing any debris or varnish buildup, and use a carburetor cleaner to restore its efficiency.
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