Rpm Fluctuates at Top Speed<br />My 1973 Mercury 1500 (150HP Inline 6) is surging and bogging down at top speed. It only seems to occur at top speed. The primer bulb does not seem to stay hard on its own. It also is a very difficult to start and takes some time to idle properly. Once its warm it runs great and also runs strong pulling tubes at about 3/4 speed. I haven't cleaned the carbs, replaced plugs, or cleaned fuel tank yet but that seems the next step. Any other suggestions? <br /><br />Gotta luv the old Keikehaffers! 
Is that Keekhifer or Kikeheffer?
Is that Keekhifer or Kikeheffer?