Dude53, can you tell us more about how your boat is equipped, and where you are located? Also, it would help to know how the shop winterized the boat. Did the shop just drain the engine and drive, or did they change oil, service the engine and drive, fill the engine with antifreeze, etc. Sometimes it is hard to say what someone else did or did not do while winterizing the boat. If there is antifreeze in the engine cooling system you will have to decide how to remove and dispose of it. Make sure you have engine oil and that all cooling system hoses are connected and plugs are closed.
Connect water to muffs on the outdrive and start it. Watch your gages and look for leaks.
If you have air conditioning or a generator, you may either need a special adapter for a water supply, or just wait until you launch the boat to operate these systems.
Make sure the fresh water system is put back together. Some people will disconnect the plumbing to drain the system. Fill the system and run water through all faucets. You may need to remove aerator screens at each faucet and clean them if there is any debris in the water system from sitting over winter. You'll notice faucets are slow or don't flow right if you have clogged screens. Antifreeze in the fresh water system may leave a residual odor or taste. You can neutralize this by 1 or 2 doses of bleach / water through the system. Let each batch of bleach water sit for a while, and then run a dose of vinegar water through the system, fill it with water and go have fun. Whatever you do, DO NOT turn on the water heater until it is full of water! I have heard some people say that they use the cheapest vodka they can find instead of RV antifreeze in the water system. I'm thinking that you can always tell when that boat comes out of storage. Everybody is showing up with jugs of orange juice to help drain the system
