Thanks for your reply David
Yes you are right , when in b button at 4000 rpm foot off blue smoke. I am not a mechanic but handy so please tell me where valve stem seals are 0n a 380 sec w126. hence there is no blue smoke on start up and when its in neutral it will rev to 6200 rpm with no smoke and also engine sounds fine , im stuck not knowing what to do now.think ill buy a service detail manual and start stripping starting with the airfilter and see whats underneath , do you agree or otherwise.