How do you adjust the high speed mixture screw? I have a Ryobi RLH1100a MK III 31cc line trimmer, and after changing the fuel lines, it will start but not idle more than about 3 - 5 seconds before it stalls. My manual points to the carby and any adjustments I have done have not helped. The manual specifies adjusting the idle mixtures 1 1/2 turns counterclockwise after screwing it in all the way, but no adjustment for the high speed adjustment stating " no high speed adjustment is possible", however there is a taller adjustment screw. Does anyone know how many turns this high speed adjustment screw should be unscrewed to start with?

Hi montex124, I will try to help. In the past few years carb makers have been making changes. Some carbs have no adjustment at all, the ports are all fixed inside the carb. Other carbs have only the idle speed mixture screw that can be adjusted, like yours seems to have. Is this screw you mention at the top and completely outside of the carb to adjust the throttle? If it is it's probably the idle speed screw which can be adjusted to any idle speed you want and has nothing to do with the air fuel mixture but If it is right next to the idle mixture screw, it might be the high speed mixture screw but is capped so it can't be adjusted. The low and high speed mixture screws should be marked next to each screw H and L.
The 1 1/2 turns suggested is sometimes just right but other times has to be adjusted, so you can try adjusting it to get your idle but maybe adjust the idle speed screw first to get a higher RPM so it doesn't stall on you. Like I said earlier it just adjusts the throttle, and is like when you are using it, and giving it gas as they say. I hope this helps just a bit. Regards and good luck. Get back to me if you need more help or just let me know how you did. Denis.