Nathan,
The 20 hour service used to include checking engine alignment, gimbal, oil change and filter. I think they changed it to a 100 hour service pack. If you are going to change the oil yourself just get one of the oil pumps from West Marine or your local dealer.
If you have any doubts about the cost, just ask your dealer. They should be able to provide you with a list of covered items.
Read your manuals as well. They should list what to do when greasing the gimbal.
Good luck,
Kerry
"I would rather be lost on the lake than found at home"