I am the new owner of a pair of 225 yamaha 4 strokes 2003 models with 425 hours and have read a few threads with horror stories of corrosion problems inside the motors and exhaust ports. This has probably been beat to death, but since the motors are new to me I would like to know from some experienced owners or mechanics on this issue. The motors are well maintained and flushed every use religiously from previous owner. Are these isolated instances due to lack of maintenance or electrolysis or is this really a problem with this motor?