Ryobi weed eater ONLY RUNS WITH CHOKE ON HALF WAY

Most common problem with weed eaters is the small fuel line breaks off inside of fuel tank usually flush with top of fuel tank - check to see if fuel line is still connected to weighted fuel filter inside of tank - replace if necessary. If fuel line is intact then adjust High speed adjusting screw 1/16 counter clockwise to allow a richer mixture - special tool may be needed to adjust - available on ebay. "https://www.6ya.com/callphilipforhelp

chokes are an obstruction placed over the inlet to increase the vacuum in the carby and cannot be pressed
Primer bulbs are used to suck fuel through the diaphragms to expell all of the air in the system to allow starting
normally press the primer bulb until it is full of fuel
apply the choke and pull until it fires
remove the choke and at full throttle pull until it starts

Did you check the muffler exhaust or spark arrester, to see if it is clogged from using to rich a oil/gas mixture ? Did you replace the diaphragm in correct position ? Find a new carb online, possibly ebay ?

change the fuel lines over on the carby
you are trying to feed fuel through the primer line when the engine is running and that is why it is cutting out

Hello Tony Galvan, I had to replace the fuel lines to keep from sucking air when I pressed on the primer bulb. Also, I took the carburetor apart and found the gasket was good by holding it up to the sunlight, no light came through indicating holes in the gasket. Then I took a magnifying glass and looked at the bottom half of the carburetor and noticed that a soft film of what looks like lint from a dryer had accumulated on a screen mesh type of filter. Once I cleaned the debris away, the weed wacker started every time. I pulled with a full choke and partially wants to start. Then moved the choke to half choke and pressed on the throttle fully and pulled, it started! But you must at least hold the throttle close to full until 10 seconds for the engine to warm up. Then move the choke to idle. Hope this helps.
peterjb1

Hi There, Check the primer bulb for tare or pin holes. Replace it. Check and clean carb jet it maybe plugged with debree. Also check for spark which you didn't say. Replace with correct plug.
Note; Do not use strong cleaners on rubber seals (O rings and gaskets) They dry up and crack.
If needed use a dabble of grease on seals

This is an ongoing issue for users, and rightfully so. Small diameter line out of fuel tank (has filter in-tank on end) connects to the side of the carburetor that has the fuel pump....that is the cover without the hole in it. Other larger diameter fuel line out of tank connects to the longer nipple on the external purge/primer bulb. The bulb "pulls" fresh fuel from the fuel tank to the carb and then out of the carb to itself, where it then pushes any air/old fuel back into the fuel tank. The remaining larger diameter fuel line in this setup goes from the metering chamber (has cover with writing on it and a vent-hole) side of the carburetor to the smaller nipple on the purge/primer bulb. Years ago on 2-stroke trimmers, primers were not even used,...you choked the carb with a slide lever and gravity let fuel enter the carb from above...a few pulls, a "pop"...slide it off of choke and away you went.
If the purge/primer bulb is on top of the carb...small line from carb body to small hole in tank with filter. Larger diameter line goes from the bulb on the fuel pump side of the carb to the larger hole in the fuel tank where the line is held in place with a nylon nipple connector that keeps the line from pulling out of the tank.
Please vote on this solution.

This is an ongoing issue for users, and rightfully so. Small diameter line out of fuel tank (has filter in-tank on end) connects to the side of the carburetor that has the fuel pump....that is the cover without the hole in it. Other larger diameter fuel line out of tank connects to the longer nipple on the external purge/primer bulb. The bulb "pulls" fresh fuel from the fuel tank to the carb and then out of the carb to itself, where it then pushes any air/old fuel back into the fuel tank. The remaining larger diameter fuel line in this setup goes from the metering chamber (has cover with writing on it and a vent-hole) side of the carburetor to the smaller nipple on the purge/primer bulb. Years ago on 2-stroke trimmers, primers were not even used,...you choked the carb with a slide lever and gravity let fuel enter the carb from above...a few pulls, a "pop"...slide it off of choke and away you went.
If the purge/primer bulb is on top of the carb...small line from carb body to small hole in tank with filter. Larger diameter line goes from the bulb on the fuel pump side of the carb to the larger hole in the fuel tank where the line is held in place with a nylon nipple connector that keeps the line from pulling out of the tank.

I have a ryobi doule line bought in 1997..Had same problem put new gas cap on and problem solved..could not get air in....

Need to get the carb rebuilt..