hey gmax, today i got a syringe and the fuel and injected a bit into 3 of the brushcutters except the green ryobi which i have taken the carby off. the Mc culloch 200A fired brilliantly and lasted for about 5 seconds on the little fuel i injected. it has a full tank where im getting the 40:1 mix at the moment but the fuel line is old and crusty so it leaks out quite a bit. im very happy with it. the jonesred also fires but for about half a second without fuel in the tank. the ryobi grass scorpian dose not start up. i have some pictures of the cylinder and crank of the ryobi lawn hornet. there is carbon on the crank so should i be worried about that?
[Linked Image from i181.photobucket.com]
[Linked Image from i181.photobucket.com]

my stihl FS 56 brushcutter has these strange screws. i have tried screwdrivers and allan keys but none of those work. do i need a special tool for the stihl?
[Linked Image from i181.photobucket.com]

last thing, on both of the ryobi's there are stickers that say 77dBa. what dose this mean?