When weed eater is running in order to get the head to turn i've got to give it full throttle before i can cut the grass, and it still bogs down.

Usually the cutting head will have a couple of plastic tabs you push in to release the spool cover and get access to the spool

If the line is spinning but not cutting then most likely you have wound in the reverse direction.

Start with carb adjustment. Turn out the low and high adjusting needles 1 full turn, then adjust the choke.

check the compression on your weedeater low compression will cause this

Make sure fuel is mixed correctly, make sure the choke isnt stuck on aswel, ive had it happen to me before when the little blue leaver sticks and it wont rev out properly.

Check these out...

And...

And one more...

Remove the cutting head spool and see if you have old grass stuck around the shaft area that could be causing to cease your shaft..

Hi goldengear...

Make sure you have installed the blade on the right way, if it is installed upside down then it will "beat" the grass instead of cutting it and make a terrible cut, also make sure the blade is good and sharp.
The rough running may be due to trash in your carburetor, I would advise to clean your carburetor and also check you fuel tank for trash, water,etc. if there is any trash,water,etc in there then you need to also clean the fuel tank.
Do one more thing and check/clean/replace your fuel filter if you have one.
Please take time to rate me

have to adjust the high on the carb. should have, 3 screws, 2 that are together is your h for high, and L for low. the one by itself is for idle. when mackine is running, squeeze throttle and adjust the high til it clears up, if it stalls real fast, back counter clockwise while off, and try to restart it, if worse, go the other way. i do mine by 1/4 turns. keep count of turns in case your going the wrong way! hope this helps!

I think a new carburetor kit and a good carburetor tune up is in order my friend. Sounds like it's starving for gas. If it bogs down after warm up when you throttle it, then yes it needs a carb tuning. The L screw is the low side screw and should be turned in lightly until it seats then back it out one and quarter turns (1 1/4). The H screw is your high speed screw. Also, turn it in lightly until it seats, then back it out approximately a 3/4 turn. With these settings the unit should start and may even stay running. Again, if it bogs when throttled, while running turn the L screw out a little more maybe only 1/16th of a turn and then try it again. If it does rev then you'll have to adjust the H screw in about a 1/16th of a turn. But make sure you only do this after the engine has warmed up.

Hope this works, good luck
Skidooer