I have a featherlite weedeater and after it runs for a few minutes, it will idle just fine, but when I push the throttle, it speeds up, then dies.

After that, its very hard to start.

Bet it's starving for air. Check the air cleaner.

Other possibilities are throttle problems and just a general tune up is needed.

The hard starting is probably because the device is flooded.

Check for fuel filter in line or in the fuel tank. The symptoms you have sounds like the carb is starving for fuel after it revs. That is also why its hard to re start.

If it was starving for air it would smoke a bit ot slow to rev like a motor on full choke.

Not familiar with the exact model but fuel to air is the same on combustion.
Check for dirt in tank and lines and make sure its ALL new gas and not last years gas which is usually the problem.

Also stored gas in a can from last year is usually also the problem. 2 cycles are fussy when it comes to gas.

9 chances out of 10 its old fuel or fuel filter in tank clogged

Thanks for the advice. It helped.