Plain clear water indicates only that you need to find out where it came from as above. Shouldn't hurt it any, but small low speed passages may have water in them as well and you will have to clear them with compressed air. Find brown goo, brownish or greenish deposits or some stuff that looks like tree sap, you have a case of varnish and will need to examine ALL the lines as well as the fuel pump diaphragm for deterioration from the bad fuel. It eats everything. I have found the use of OMC Engine Tuner will clean the carbs without exposing you to caustics, has no unpleasant odor and it rinses away with water.
Similar products are available from other manufacturers.
Many of todays modern engines have some sort of oil premixing or injection system, you need to examine this system closely as well. If you are experiencing excessive oil usage on an Evinrude or Johnson equipped with the VRO system, look for an air leak on the fuel side. Air leaking will cause the oil side to add too much for the imaginary gas that is actually air. Motor cover is a machinery guard. Use caution when conducting tests on a running engine.