Water inside cylinder when left unused in water 4-tec 2002 155hp

[Saku]

Have driven this summer 250km and this works fine, but if I leave it at the lake for a couple of days or a week or so, it won't crank over. Thought battery is drained, but now it seems there is fresh water inside the cylinders and that is why it won't crank. Have removed the plugs and they have drops of water. One can see water surface over the piston. Cranking plugs removed, water is sprayed all over (photo). Then install spark plugs back and go to a ride no problem. Sometimes cranks and starts ok, 3 times this far needs water removal by cranking without spark plugs.

Coolant fluid level is full and has stayed there this summer since I got/bought this. There is hardly any waves at the bay at my dock, 20m away from my house.

What could cause this? Leak at the exhaust system? Missing parts or wrong assembly of water hoses or such? Could it still be waves coming in from the exhaust? Owner manual says max towing speed 20km/h.

 

[skiasylum]

Most common, submerged ski, improper back flushing of exhaust, and towing. Does your engine oil look milky? Pull your exhaust and see if there is water in the muffler.

 

[mkov608]

My owner's manual states skis are not to be left in the water. You'd better perform the repair steps for a submerged ski quick, or you'll have a lot of corrosion in the engine.

 

[Saku]

Oil is good, has stayed at the full mark. No milky, looks like a new oil. Changed the oil a couple months ago.

There hasn't been any water at the hood when driving. Driven only on calm lake. Has not been towed. Front compartment and bilge are dry and have been dry when water has managed to find a way at the cylinder when laying at the dock.

Put the spark plugs back and drove half an hour, no problems. Left to the water for 4 days. Today pulled out the plugs, without cranking the engine first, and they were dry. Also cylinders were dry. Didn't try to crank and start the engine. Will disassemble the exhaust to see if there is any water.

Understandably not to be left to water for weeks or days. But don't understand what causes this. Long time shouldn't cause water to rise anywhere. So if 5 days is a no, then also 5 minutes at the water engine shut off should be denied because it may cause engine damage. If wave causes it, if a boat goes nearby or such. If waves causes engine damages when engine isn't running, we all would be aware of this phenomenon?

 

[skiasylum]

Your open loop cooling system uses outside water to cool the exhaust. If it's not back flushed regularly that system is prone to corrosion especially in salt water.