Check out my thread when I had the same problem -
http://forums.iboats.com/forum/engin...ck-suggestions
I took my boat to several service shops and they all said there was nothing they could do to help me.
My problem was that the outdrive had seized onto the corroded mounting studs - lots of white powder and the outdrive wouldn't budge. My boat was in saltwater for a bit (PO) and it reacted violently with the aluminum outdrive and steel studs apparently. To make a long story short, I used heat, break free, pressure, the wood block and trim up trick and nothing would work. However I'd say that pinching a wood block at the top of the outdrive and trimming up put the most and safest amount of outward pressure on the drive of all the tricks I tried. DO NOT thread an eyebolt into the dipstick hole and try to pull from there.
You can also try double-nutting the studs to see if you can back the studs out -they are just seated in the gimbal housing with a reverse thread.
I ended up pulling the outdrive off by removing the hinge pins and then working on the outdrive on the bench. If yours comes off this way then its obviously not a seized drive shaft. I then had to smash up the gimbal bearing to release the studs and get the outdrive off.
Since then (which was my first winterization with the boat) I've coated the studs with marine grease - its been a piece of cake year after year now with no problems. All in all, the replacement gimbal housing about $180 - so it wasn't bad.
Hopefully yours won't come to that. Try the wood pinch trick and if that doesn't work, try double nutting the studs.