If you are really worried about it you can also just stick a light bulb on a drop light under the cover. But I would think even at a few degrees below freezing over night assuming some 50 degree temps the day before you'll have to shed all the heat built up over the previous day and then will still need a fair amount of time to freeze solid.....you'll be fine. But like said if it makes you sleep better drop a light or heater in there for a a buck or 2 in electricity.
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1986 V-20
1986 Yamaha 150 HP
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