i am about to buy a 40hp merc and it seams to be having problems when
in idle. If i run the engine in idle (not in gear) it will stall out
and shut off.

EX - pulling lobster traps once i get to my trap and pull it up and
leave the boat in nutral it will stall out.
and when i start it up if i take the choke off of it and let it
be it will also stall out.

other then stalling out when the engine is not in use there is no
problem. it starts up flawlessly even after stalling out but it would
be nice to make sure i can fix it before i buy it.

my question is is this something i can fix myself or am i going to have
to spend a few hundred and get this boat tuned up by a mechanic.

i could be wrong but i think the carberator needs a good cleaning. the
engine is 2-3years old 40hp Merc 2stroke