Fully inflate the tubes and check for leaks.
Check the battery terminals and the condition of battery.
Turn the steering and check for ease of use.
Turn on the electrics and check the switches work (bilge - nav lights - radio) etc.
Fill the fuel tank and add 2-stroke oil if required.
Check the engine oil levels (gear box -top screw not bottom).
Grease where appropriate with a gun.
Fill the 2-Stroke oil resevoir.
Take a quick look at the spark plugs to check they are tight (they may have been released following winterization).
Take a quick look at the petrol filter, is it clean and full ?
Do all the leads look connected ?
Is it free to roll and if so is it capable of getting you to the launch site and back ? Ideally service this when you can (hubs - brakes - jockey wheel) etc...
Do the lights work - number plate !
Connect your "phones" to the leg og the engine and turn on the H2o.
Prime the engine squeezing the bulb/pump on the fuel line until it's hard. There may be two depending on your set up. Release the small air tap ontop of the tank(s) if appropriate.
Initiate the choke either maunally or if PTT it may be an auto choke on the key by pressing it up as you turn it. Make sure you are out of gear and give it some throttle.
Turn the key and let the engine turn over for 5 seconds or so and stop. If it fires at this point give me your telephone number and I'll buy it off you
Pump the fuel bulb(s) once again, check the choke remains on and turn the engine over for another 5 seconds.
At this point and with hope the engine is turning over and it's just a matter of getting it to start, once the fuel hits you're away. Once your all fired up let the engine run for a good 5 minutes just in case it has been winterised, in this way you'll clear any oils and aditives in the engine.
*Make sure water is flowing from the engine* if not stop and seek professional advice (I'm a speciality chemical salesman not a mechanic) !
If however it doesn't turn over.....check the battery, fuses on the engine and behind the dash and give the solenoid a tap - if in doubt, tap everything with the handle of a screwdriver. If it still doesn't start check all the leads, plugs, fuel line connection, filters etc.
Good luck, let us all know how you get on.
Make sure you have an anchor, mobile phone, tell someone where you are going and what time to expect you back and for the first run stay close.