WELL, it WAS a stuffed drive belt but i'm glad i delved. Very little oil in the transaxle and overfilled hydro pump. NEW fresh oil applied and right amount. Couple more questions. Can worn pulleys prematurely wear belts? not as in bearings worn but the surface of a pulley? Just wondering how long this one i put on should last, it is used, off my ST160, but i don't fancy replacing it again any time soon as it takes a bit to replace. The fuel cap has a plastic clear dome so you can see the gauge ,this is broken so dust and moisture can get in there, i was going to plug the tiny hole in the centre but the tank needs to breathe, any suggestions?

Thanks, glad to be cutting grass again!!