How can I fix my Mcculloch 280b gas blower. ?

My blower starts and stays running for about 5 to ten minutes. It acts like it is going to die. I start using it and I don't know it seems to start to dye when I put the knozzle toward the ground. In the manual it says the clean out the air and fuel filter. So far all I have cleaned was the air filter. The filter seemed clean when I took it out, but I cleaned it anyway.