Blower: Only Runs With The Choke On

The choke in your leaf blower draws fuel into the carburetor. It is used to make a cold engine easier to start. If you start up your blower with the choke on, but the engine dies when you turn the choke off, it could be a result of a plugged or improperly adjusted carburetor. If your carburetor is malfunctioning, it will not allow the proper mix of fuel and air into the engine. The choke can temporarily solve this problem when you turn the blower on, but as soon as the choke is disengaged your engine will die. If your carburetor is damaged, you may need to replace it entirely. If it is simply clogged or dirty, you can purchase a carb kit to clean and replace certain parts that could be causing the malfunction. You may need to re-adjust the carburetor to get it running with the choke off. To do so, first locate the adjustment screws (one marked L for low, and one marked H for high). Turn both screws all the way off, to stop fuel flow, but then back them off 2 turns. Turn on the engine and allow it to warm up. Turn the L screw clockwise until the engine slows. Then, turn it counterclockwise until it slows again. Set the adjustment screw at the midpoint of these two turns. Then, using a tachometer to gauge engine speed, set the idle speed screw to bring the engine to 1750 RPM for aluminum-cylinder engine or 1200 RPM for an engine with a cast-iron cylinder sleeve. At full throttle, turn the high speed or main jet screw clockwise until the engine begins to slow. As before, now turn the screw the other way until the engine slows again. Set the adjustment screw at the midpoint of these two turns.

If your carburetor is clogged, it can cause your leaf blower’s engine to die when the choke is disengaged. You can disassemble it, clean it, and replace individual parts with a carb kit. Once your carburetor has been unclogged, cleaned, and re-assembled using the carb kit, the engine should run with the choke off. If your carburetor is damaged, it may need replacing.