The gas engine on your leaf blower needs to operate at a specific temperature: hot enough to burn the fuel and give the engine power but cool enough not to overheat the piston. An overheating problem in the leaf blower is generally caused by a failure to vent gases or the fuel burning too hot inside the cylinder.
Improper Fuel Mixture
All two-stroke gas engines on leaf blowers are combustion types without an oil pump, so these models require fuel that combines the gasoline with engine oil. The lubrication for the piston and crankcase comes from this fuel mixture. The oil in the fuel mixture also helps keep the fuel from burning too hot while protecting the cylinder and piston from too much friction. Check the fuel mixture that is being used in the leaf blower and make sure there is sufficient oil in the mixture. If enough oil is present, according to the manufacturer's specifications, add a little more oil to enrich the formula: about 30-to-1 gas to oil.
Dirty Air Filter
Another common reason for the engine to overheat, seize and die is a dirty air filter. These filters screen out any dust or particles that could enter the fuel and reach the cylinder. If these filters can't bring fresh, cool air into the engine, the gases will back up, and the engine will shut off. Wash the filter pad regularly, after every couple of uses, in a mild detergent, such as dish washing soap. Rinse the pad in cool water and let it dry overnight; and if it's too dirty to clean, replace the filter.
On the other end of the air supply, the muffler vents out heated gases from the cylinder. If too little gas is escaping the cylinder, the engine will quickly overheat and die. Most leaf blowers use a spark arrestor screen. While these screens are important to prevent fires, they do tend to clog up a muffler if they're dirty. Pull the spark arrestor screen out of the muffler and scrub it in soapy water. Replace the screen if there's too much carbon on it to clean it.
Compression Sealing Problems
When small engines start to age, they develop sealing problems around the crankshaft and cylinder. The gaskets holding the airtight seal tend to break down and crack, allowing air into the engine and resulting in a loss of compression and a seized engine. On the other side, too much compression in the engine will also cause the engine to seize up. These gaskets require a professional to split the crankcase into its separate halves and check the piston for scratches and other dents, which could also be causing the seizing problems.