very common..
take off the top cover and underneath you will see a torx screw to take the cam cover off.
lift this off and you will probably find that the exhaust cam lobe has melted.
I have one, and if you look on youtube a lot of people have the same problem.
like rocking horse shit to replace as they don't make one, but will sell you a complete unit for amout £90.00.
Being a 4stroke engine it is only good for strimming as the oil must stay at the bottom (sump) when lifted to cut hedges ETC it will suck oil up into the breather until none left. so check and see if there is any oil in it.
Don't throw it away as with a bit of thought it can be repaired.
I'm in process of trying to get a cam made for mine (metal)
I will check this site and see how you get on. keep in touch....
colin, March 2014
