82Kreinbring
New member
Hi guys, I'm pretty new to boating and I could use some advice. I have a a vibration issue with my 1996 mercury 200 efi. I don't have any realistic options for a marine repair shop so I'm hoping to fix this myself. Here's the story. I just bought the motor to put on my 1996 lund baron 20'. I ran the boat for years with a 175 Suzuki and never felt a vibration in the floor until I recently installed this mercury 200. The transom on the baron caved in about 5/16" but I didn't want to replace it yet so I installed the mercury right to the transom. I put it on the lowest mounting holes which for some reason still left the cavitation plate about 1" above the bottom of the hull. I used 5200 sealant and tightened the bolts to 60 ft lbs. When test driven I felt a heavy vibration in the floor which got worse the higher rpm and lower down I trimmed. My prop is a stainless 5 blade that looks decent. There is about 1/8" front to back play when I pull on the prop but no side to side play that I can feel. The lower unit oil is milky. I actually bought the motor on an old fiberglass boat that I just scrapped. It had a 12" jack plate and i never noticed the vibration when test driving that boat. I noticed the milky lower unit oil but it shifted fine and didn't notice excessive metal when I drained it. Any advice would be appreciated.