Thanks for the hints......i cant chk compression here at the moment, but when I had the cyl heads open the sleeves and rings seemed like new..as the first owner claimed (with paperwork ) that he'd only done 80 hrs on the engine, and I have since done app.100hrs. rings have no play restriction and float freely.

Timing WOT is 20degrees

carbs and throttle body are clean...was a bit of dirt in the throttle bodies (like fine rust)
I installed an extra fuel pump just in front of the rubber ball pump...and now get the engine revs to 4000-4200rpm but not higher..the engine takes throttle much better though.
I forgot to mention the first time that the "chk eng" light is mostly on...but it stays like that after turning on ignition...without the engine even running. According to manual that means fuel or ignition problem. Without a fuel pressure gauge..how do I judge the correct fuel pressure? I guess after VRO pump?
rgds
Stefan