Hello is it ex hire shop machine ,Camon changed the C8 about 4 years ago from 3 forward gears to a single forward gear especially for hire shops ,main problem was idiots on the handle bars ,(I know 2) not using the machines properly rotor speed should be as engine speed they are clutch off the engine maybe gear box is worn out ,a simple test is to engage rotors before wheels rotors should push machine along if rotors stop when wheels engage the gear box could have problems ,dont do this test near a green house ,I once put a Howard gem rotors in gear before the wheels it set off across the greenhouse made it's own door way jezza