1999 Mariah z302 with a Gen VI 502 Magnum efi with a Bravo 3 drive. Have about 257 hours on the engine after a rebuild in 2004. I normally keep the boat slipped at a local lake in the summer and am planning to do so again this year, but I am worried about any bellows, seals, or rubber parts in the drive and transom assembly that might leak water into the boat at this stage of it's life-- 12 years old.

Are there any bellows or seals that I should have replaced or at least checked to insure that I don't show up some day at the marina to see my boat hanging by it's lines and under 3 feet of water????

Other than a visual check of the bellows-- is there anything else I should do/have done??

Time to do the bellows, and keep the service order for insurance purposes. I had an agent tell me once that they look at the time the belows has on it if the boat goes down (and he said bellows was big cause of this). He was visiting me because someone made off with my aluminum trailer in 2008.

At 12 years the bellows are overdue to be changed. Make sure you get the shift cable bellows changed as well. A leaking shift cable bellows can also sink your boat.

whenever you leave a boat in the water dont matter how old its prone to a leak. There is nothing that man built that god cant sink. Some slowers than others but all will sink with time