drawing too much current possibly due to extension lead too light,the longer the lead the more voltage is lost, or fault in motor,make sure power supply is compatable with current draw of saw.Should use a residual current device RCD and get it checked by a professional electrician
Dave Fix
May 2011
Automatic Answer
While you wait for answers, we may have found some information which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix chainsaws.