Ryobi 3046YE, idles too fast & stalls when you use throttle, any ideas ?

I have a 2 year old Ryobi PBC 3046YE which has recently started idling really fast and stalls as soon as you use the throttle trigger. Have recently replaced primer bulb, but also the idle cam doesn't actually touch the idle screw adjuster... could this be the problem ? If all else fails will take it in for a service, but its hardly been used & you hear scare stories about Ryobi being cheaper to replace with new than repair !! Any help gratefully received. Thanks.