Hi, Dont know if anyone can help or suggest anything... I am not particularly mechanically minded so any advice would be very gratefuly received! About a month ago I bought a brand new Mountfield SP164 lawnmower, its worked fine for the first 3 mowings but today for some reason it will not run evenly. So it sounds like its revving up and down (brm brm brm....that sort of noise!) I can see a vertical lever on the side of the machine that I assume is the throttle maybe, if I move it the engine will speed up, this lever is moving back and forth of its own accord creating the revving up and down. The spring and cables that are attached to it appear to be ok as far as I can tell. The only advice in handbook about engine not running evenly is make sure the fuel is not over a month old. Well its probably been in there nearly a month but I really don't think this is the problem. Anybody got any ideas please? Many thanks.