Re: mercruiser clunks then stalls
The worst thing that can happen is it can wreck the engine. The good news - it often won't do any lasting harm. Pull the plugs and crank the engine, you'll know pretty quick if it was hydro-locked. If it was, you need to solve the problem and get the water out of the crankcase, where some will most certainly be hiding. The best way to get it out, IMHO is to suck/drain from the oil pan until you are only getting oil. You will not get all the water this way but you will get most of it. Then take the boat out for a good 1/2 hour run to boil off what you can and mix the rest in well with the oil. (Yes, oil and water will mix if you stir real well and squish it through a bearing). This isn't good for the engine but it's the only way I know to get the water out of the hidden corners. Sea-Foam is well spoken of and claims to pull water out of oil so you might consider adding some before the run. Then change the oil as soon as you can after the run. Make sure you do this soon because if water is in the engine right now you want it out before it does any damage.
