[Mo]

If there is antifreeze in it you might smell the antifreeze. If not, well the loss is very minor and not likely the cause of the white smoke.

Here's something that does happen in spring and fall. The actual exhaust air is warmer than the ambient air temp outside. At this time of year it's not uncommon to see a white smoke, especially in the morning where the ambient air temp is cooler. You might have a combination of both going on as well.

The coloring of the exhaust, after sitting two weeks, is not uncommon. Water is sitting in the exhaust system, there's a bit always sitting there somewhere and it does get discolored. If it clears in less than a minute that would be normal. I'm raw water cooled and if the boat has been sitting the exhaust will look dirty initially.

I'd just keep an eye on the reservoir for now, take a book and monitor the hours used and if you have to add antifreeze. Watch the temp gauge closely as well and see if you are heating up under load.