Ryobi trimmer plus won't start. No sound at all

replace the starting pull cord Graeme, Check the attached links,instruction and guides, Good luck
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WeedEater string pull repair STRING WON RECOIL FeatherLite XT260

Fixing The Pull Cord to STIHL Weedwacker

How to Fix the Starter on Ryobi Trimmer

String Trimmer Starter Repair

It appears that the recoil spring has broken and you will have to pull it apart to replace it

the ryobi expand-it is just a power head ( motor ) that you can attach any ryobi or like attachment to
There is no reason why attaching a pole trimmer would affect the recoil of the starter rope as it just slides onto the drive at the end of the shaft
the fix will require the removal of the cover and the tool will be in a selection of bits that you can get from a good tool shop or auto parts shop
from memory it is a 6 point star around 3mm in size
the failure to recoil is normally a broken coil spring

full choke on , push petrol bubble 5 times then pull starter cord., with luck it will kick in to life after a 20/30 secs put on half choke , run again for 30 secs the no ckoke.

The main problem with Ryobi products is that they flood very very easly. So the more time you try and pump petrol into the carb the more it will flood . If that happenes then choke off and switch off and then just pull starter cord for about 30 secs then switch on and it could start if not prime it again as above good luck

You didn't list the model but those little rewinds are typically built very similarly.
It may sound a little crazy but it works, take the unit to a power washer such as a car wash and blow out the gook in the rewind with lots of hot soapy water and then rinse. Then using a probe or small screwdriver get the rewind unstuck. If it retracts you’re good to go if not let me know as you may have a broken piece in there

how do I repair/replace the pull cord on my Ryobi CS30?

My Ryobi 890r brush cutter will start and then die

YOU CAN ORDER ANY RYOBI SPARES FROM YOUR NEAREST MICA AND THEY WILL ORDER IT FROM RYOBI (011-805-5540) AT MIDRAND. LEAD TIME TWO DAYS

What model number is your Ryobi?

you have to remove the starter housing, inside will be 2 knobs that spring out when the cord is pulled that contact the flywheel cap of the motor and rotates the crank. check if they are missing or damaged and that they ejecting when the cord is pulled. if not; replace.