D. H. Pascoe & Co., Inc. Marine Surveyors, Destin, Florida
http://www.yachtsurvey.com/winter_lay_up.htm
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Maintenance and Trouble Shooting
Winter Lay Up
by David Pascoe
...................edited by TRO
Fuel Tanks
There is plenty of controversy about whether gas fuel tanks should be empty or full at layup and you can find reasonable arguments for either condition. However, the argument for leaving them full overlooks the fact that modern gasolines go bad much too fast and six months is FAR too long. Old gas will definitely harm fuel injected MPI systems. Moreover, diesel oil is subject to bacterial blooms and oxidation as well.
Condensation developing in the tank is a much over-rated problem and here is the reason why: An empty tank contains a limited number of cubic feet of air, and therefore water vapor that could possibly condense. Air does not flow in and out through those tiny vents, plus you can always tape the vents over if that bothers you. The amount of water vapor in the tank comes to several ounces. However, if you have good Racor, Dahl or similar filters (which you should) these will easily be able to handle that amount of water. Smaller canister filters will be strained to get that much water out, but the large types like Fram cartridge filters can handle it.
What about fuel stabilizers, biocides etc.? While I'm not a petroleum chemist, I do know that these potions have a less than spectacular record of success. Personally, I'm not a believer in miracles sold in a can.
Therefore for both gas and diesel boats, it is best to arrange your fuel situation that the tanks be as empty as possible before you take the boat to the yard. Old fuel is a greater problem than a little water in the tanks.
Should tanks be completely drained for the winter? No, that isn't necessary. Besides, if you do, you'll have to refill them from 5 gallon cans in the spring which is messy, hard work and dangerous with gasoline. Leave just enough to get the engines started in spring and get to a fuel dock.
The old fuel left in the fuel lines is one of the reasons we have so much trouble getting engines started in the spring. In the spring you can bring a gallon of fresh fuel and prime the filters with it for easier starting.
Engines
Regardless of type, it's best to flush the systems with fresh water. Do this immediately before haul out. Close off the engine sea cocks and place a hose in the top of the strainer and run the engine at idle speed for 5 minutes. The objective here is to clear the saltwater side of the system. If you're doing it yourself, you do the engine fog-out at the same time.
Engine oil and filters must be changed before layup because of the acids that develop in the oil that attacks bearings, plus that's one thing less to do in the spring.
The engine air intakes should be taped closed with duct tape, as well as the exhaust pipes to prevent air flow through the engines.
Check the mufflers to see if they have drain plugs. Many don't and if not you should ask the travel lift operator to raise the bow of the boat to get the residual water out of the mufflers.
Hybrid Mode
