Well, you should be seeing 70 mph for 3500 rpm. But for $200.00 whadda want??.
!!! The hesitation could be a number of things, fuel starvation, dirty injectors, ignition and so on. I am not that familiar with that year 190e, but if it is not fuel injected and has a carb, you have a huge flat spot. Maybe Steve or Donnie can get more specific, or maybe you know. Is it injected or carburetored? The bottom line is there are a number of possibilities for the hesitation. You may have to have it checked by a competent tech.