Thanks Grumpy, i got it running today after stripping and cleaning the carb. Diaphragms were in good shape so i reused them. Yes, youre right, it starts best when both screws are right in although still wont take full throttle. Once you try to load it up it dies although idle is sweet. Playing with the mixture screws has little effect. Tomorrow i'll change the pickup filter and remove the mesh filter in the carb and see if that helps.The carby is a mexican made Walbro but i cant remember the part no. on it now from memory, but i'll note it down tomorrow when i pull it off again. Oh, and thanks for the links, the owners manual in particular is very handy.