Weekend boaters checking the oil before starting should be suspicious of oil levels that are too high or too low. Too high a level might be a clue that water has found its way into the oil sump. You could crack the cylinder head, break a piston, or both, just by turning the engine over. Too low a level could indicate an oil leak that could lead to engine seizure. Look in the bilge to see if there is any oil residue.
Many marine engines sit very low in the bilge and water is consistently in contact with the oil pan.
Over the years this can corrode and cause pinhole leaks in the pan. Whenever there is a large deviation from normal, take that as an urgent warning. Start looking for more clues or seek the advice of an expert. How, Inc . All rights reserved.