[JohnS]

A 200 on an 18'. That thing must fly!!!

Mariner, a Mercury in disguise, lower end, same basic motor though. I have had a few Mercs, the older ones are a bit noisy, especially if the cover had, past tense, insulation. If it did have some, and it is gone, you can replace it. If it didn't, and there is clearance, you can get some stuff called "Dynomat" and install it inside the cover. This will quiet the thing down amazingly well. It is used in high-end car audio applications and most car sound stores carry it. It can also be found less expensively online. I used it in a car when I was younger. Used it on a friends outboard and it made so much of a difference it was unbelieveable.

I would have the motor checked if it was unusually noisy though. Especially if you are really concerned about it. Also, look for another boat with a Mariner on it and go check it out, compare, see if it is real or perceived.

John