Re: 1999 Mercury 200 Offshore
I have owned a 1996 Offshore for the past seven years and it has run great. Water pump impeller should be replaced every three years, tops. Lower unit gear lube should be change at least once a year, more frequently based on number of running hours.
I did burn up two pistons at the end of last summer. I found a broken fuel line supplying the middle carbs and this caused the middle cylinders to run lean when I was running WOT chasing a school of tuna.
I did the rebuild myself for about $1000 and now have seven break in hours on her. So far, so good.
Take good care of it and it will be good to you!