if you cannot start your unit when hot


Your two-cycle string trimmer operates through a constant stream of air and fuel mixing in a precise balance inside the carburetor. When the flow of air or fuel stops, even a little, the precise balance will be lost and the trimmer will start experiencing problems. Most often, problems starting your trimmer when hot are located in the carburetor, but you can make some basic fixes yourself before taking the trimmer back to the shop.

Keep Air Flowing
Your two-cycle string trimmer must suck in enough cool air to mix with the fuel inside the carburetor. Dirty air filters, clogged air vents and dirty mufflers will prevent the proper intake and outtake of fuel. If the airflow is reduced you will force other parts of your engine to work harder to maintain the proper air and fuel balance.

Maintain Fuel Supply
Keeping the fuel system free and clear of obstructions will also help your engine run more smoothly. The fuel gets sucked up from the tank via the fuel pump inside the carburetor. The fuel pump's diaphragm pulses in time with the crankcase, drawing fuel into the carburetor when the pressure increases. If the fuel pump can't operate efficiently due to an improper fuel supply from the tank, your trimmer will stop working, especially when the diaphragm gets hot. Keep the fuel filter and fuel lines clean and unobstructed. The tank also contains its own vent valve to allow heated air to escape, which maintains the proper pressure inside the tank so fuel can get pumped into the carburetor. To check if your problem is the vent valve on your fuel tank, unscrew the gas cap about halfway and try to run your trimmer. If the vent is plugged, the loosened cap will allow these heated gases to escape.

Replace the cap if your vent valve is blocked.

Check for Leaks
Sometimes an air leak somewhere in the fuel system can cause your engine to stop running when it gets hot. Air leaks can occur in the fuel tank, fuel lines, and around the valves where the fuel lines connect to the carburetor. If the carburetor isn't airtight that extra air will push the fuel out of balance and force your trimmer to die. More serious air leaks can also occur around the gaskets on your carburetor, which will expand when heated, causing the air leaks to worsen.


Check fuel Mix

Fuel mix screw may be out of adjustment (lean) and causing engine to overheat. You can try and fix this by adjusting the carburetor fuel mixture screw (the one with spring). Try undoing the screw to open up the inlet (richer mixture) and allow more gas to blow through.

Service the Carburetor
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