ive got a 1997 200 venom model #j200stleub im changing the water pump this lower unit was new in 1999 has about three canadian seasons on it i was wondering if i should change the seals in the upper and lower gear case while i have it off .i havent had any problems with water in the oil so i dont know if i shoould.seals look good but can they dry out or should i wait until i see signs of a problem .thanks pat