It really does depend on what was done to it in the fall before it was put away, as rfoster indicated.
My spring time ritual is basically as follows for the 4-tec n/a engine:
-change oil and filter (I prefer to do this in the spring rather the fall, start with fresher oil for the season)
-replace coolant every 2 years (whatever year that happens to fall on)
-replace spark plugs after first start up and fogging oil burnt off
-fill up gas tank with fresh gas (I prefer to run tank almost empty, then add stabil in the fall)
-newly charged battery
-make sure all the electrical stuff works
-make sure cables are all working (should all be lubed in the fall before winter)
Then I just dust her off and hit the water. Hopefully the jet pump was checked during the winterization process to ensure it was not infected with water, otherwise you will probably have some rusted parts come spring. I don't think it is necessary to use a fuel additive as long as you used some sort of gas stabilizer in the fall (stabil for instance). A full tank of new gas usually does the trick. I may have forgotten something, and if so hopefully someone will chime in.
Oh and make sure to screw in the drain plugs before you drop it in the lake!
