After I replaced a bad carburetor on my Echo blower PB 403T and adjusted it would now run. However, when I run it at WOT it runs perfectly but it will bog down after 5-6 minutes and then shut off. I can restart it most of the times pretty quickly. I cleaned spark arrestor, muffler to motor opening, new gas filter, gas line, new gas/Echo oil mix and a new plug. I ran it with the cap off to avoid any air lock issue with the same bad result. Any help would be appreciated.