Removing trim tilt motor

[mega256]

Is there a way to remove the 4 bolts on the trim/tilt motor on a F115,
without breaking the heads of the bolts off?...My f115 is a 2003,I have the tilt trim assy. off the motor and got 1 bolt off ,broke the head on another,and have 2 more to remove but I dont want to break the head of the bolts off,,,
they are tight!

[boats.net]

Might try to apply a small amout of heat with a heat gun.