Ryobi CS30 Trimmer starts and runs in full choke and half choke but stumbles and stalls on run. Not up to full rpms when in full choke and half choke....

Dirt or varnish in fuel filter or carburator. Change filter if there is one.

Flush out the carb with a varnish remover.

Open high speed needle valve 1/8 turn farther, then turn in while running until it just smooths out.

Many times with a gas mix, after sitting for a while, the mix separates and gums up the carb. Taking the carb off and soaking it overnight in a parts or carb cleaner and running carb cleaner through the tank and gas lines will cure this.

Is the fuel old or has it been drained and refilled?? Sometimes old fuel will do this. Also make sure the air filter is clean and free of oil/dirt as this will also hinder the starting.

The primer button also is something to check. Push it 7 times, full choke, pull for 5 times, turn to half choke, and the unit should start.

Let me know,

Chip

Yes. It sounds like you need to clean the carburetor. Take the carb. off, disassemble and spray with carb. cleaner. Make sure to clean the small screen in carb. Clean the small portals with a Den Tek Brush, (used for cleaning between teeth). They work great for this job. Reassemble carb. and try starting. If this doesn't cure the problem then you will need to buy a new carb. kit and replace the needle valve, gasket(s), diaphragm, & small screen.

Jim

you probably made the mistake of leaving it in the shed over winter with gas in it.
in the carb there is a diaphgram that oumps this fuel in via the motor vibrations.
said diaphgram had been ruptured due to drying gas in the carb. the solver to this is to either have a small engine mechanic replace it or the whole carb or get a new one, and i would suggest you get the cs26 model instead. i have a cs30 and cs26 and i have had less problems with 26. it only has two chokes.
you prime it.
you push lever to start, closing all but a little bit of carb,giving engine much richer mixture.
you squeeze trigger, opens halfway/full, as there are two chokers in the carb, on controlled by lever and another by throttle.basically now you haave half choke.
you release trigger, goes back to 7/8 choke to keep at idle but not running. your ready to go.
on the cs30 its much more complicated:
ful choke
prime 7x.
pull 4x
half choke
pull till start.
wait ten seconds of running at idle rotate to run
good to go. but these guys have porr design. if you take off the back cover and look above fuel tank on cs30, the crank is RIGHT SMACK THERE and not better secured like in the '26 model.
that's what the little circular hole is in it.
anywho, the diaphgram is ruptured, and you probably haven't noticed that in addition you have gas leaking out the carb's air intake.

You need to rebuild the carburetor. You will need to go to an outdoor power & equipment store of some kind to get a carburetor kit for your specific trimmer. It will come with various gaskets, (some of which you won't use), a needle valve, and a small screen that goes in the carb. Replace all old parts with new. New primer bulb is sold seperately. When you have the carb. apart, you will also need to clean the small ports with a Den Tek Brush (used for cleaning teeth). Use carb. cleaner when cleaning.

Jim

Most likely carburetor needs adjustment.

do you have the right kmix fuel to addat start on choke let run tell it dies then pump the ball on half choke and chage the plug

Here was my solution:
I was having problems with my ryobi cs30 weedeater also. It would start up fine on full choke, but i could not give it more than half throttle or ever take the choke off or it would stall out. I replaced fuel mixture, spark plug, spark arrestor/exhaust, fuel lines, cleaned carb, and still nothing! I was considering getting a better machine. Then i decided to play with the carb adjustments.(on my cs-30, they are two screws on the carb that have a "L" and "H" next to them) I dont think you can get the specialty tool for adjusting the carb unless you are a repair tech, so i just took a Dremmel tool with the circular cut-off wheel to the head of the specialty screws and made them into "flat-head" screws so i could adjust them with a regular screwdriver (if you dont have a dremmel too, get one!) (As i was cutting into the head of the screws, i also cut into the casing protecting the head of the screws that was in the way, this does not cause any damage to the unit, that casing is only there to keep "un-certified" people from adjusting it for themselves.)
Now to the easy part: The "L" screw adjusts the idle fuel mixture and the "H" screw adjusts the full throttle fuel mixture. turning the screws clockwise make the machine run leaner (less fuel) and counter clockwise makes it run richer (more fuel).
-I started out by turning each screw 1/2 turn counter clockwise and started it up, then as it was idling, i started adjusting the "L" screw as i was moving the choke position to run, after a few full turns counter clockwise of the "L" screw, it was idling perfectly in the run position, then i did the same thing the the "H" screw while holding down the throttle and i got it to run perfectly in the run position. Now it is running way better than it ever has. I hope this helps everyone.
Good Luck!

My straight shaft trimmer will idle but dies when the I pull the trigger.