I have a Homelite Z850 gas powered weed wacker and its was running great last year. This year after I start and it runs, no matter how long it runs when I give it gas it acts like its choked, never gets to full speed and the gas consumption is very high. I checked the air filter and when I remove it the choke is clear and it appears clear but it still runs like it does when its cold and choked.

Try checking the spark arrestor in the muffler, it may be clogged.

I couldn't find any Z850 info on Homelite's parts site, but if carburetor is diaphram type, also try changing diaphram. They tend to get stiff over time or if fuel was left in machine over winter.