In the meanwhile I changed Battery, Starter and relay....doublechecked all cables and ground...all things fine...
I pulled the sparkplugs and I can turn the engine by hand....starter is not able to turn the engine....if I turned by hand and then push the button from the starter, the engine turns slowly.....if I stop and will start again, relay is clacking and starter is not able to turn engine....
Any more ideas from the pro's..?
Thanks, Stephan