New plugs. First sign of old / worn spark plug is it can only produce so
many sparks per minute. They will start breaking down at higher rpms.
Next - engage the choke when it starts to hesitate and see what happens.
If it bogs - definetly an ignition problem. If it picks up speed -
carb/injector problem.

--
Tony
my boats and cars at http://t.thomas.home.mchsi.com
"Ryan Olkowski" wrote in message
...
I have a 115hp 4 stroke mercury that runs fine at or below 3/4's throttle
... When it is pushed any further it hesitates ...I changed the fuel
filter
and installed a new seprate water separator fuel filter deal... Its not
overheating as far as I can tell ... The oil is fine always been checked
and
changed regularly .. any ideas where to start ?


Thanks
Ryan