Curious, As we were winterizing our motors we noticed four dents on the exhaust. Wouldnt seem bad but they are comming from the inside out. Looks as though the valves may have let go or something came out of the exhaust the size of a stem. Have not torn it down due to warranty.Any one else had any issues with them or any idea what would cause these dents other than a motor failure?

Would you describe them as outward dents with sharp edges, or more like buldges? Buldges are common, and are usually caused by not draining the headers during winterization, and having water freeze and expand in the water jackets.

I usually try to make sure that the headers are full of antifreeze during my winterization process.

I have seen the buldges before, but not any failures because of them.

Hope this helps,
Chris

dents the size of a valve stems a protruding nipple only on discolored header tubes. Its in a heated garage never been in freezing weather. winterized before weather turned. forgot to add the last run it had mad some major pops and bangs that could be heard from shore and not in the boat. It idles fine when we winterized it but never ran it since.To describe better looks like someone took a punch from the inside out and hit it with a hammer.

I would have it checked out by a Merc certified mechanic, especially if it is still under warranty.

Chris

Later headers now have internal separators to keep the water jacket spacing at critical points. these usually create some small dents protruding from the tube. If that is what you are seeing, shouldn't be a problem.

tthhhhaat doesnt sound good. possibilities are numerous. i would pull the plugs and inspect them. then maybe a compression test, especially since you say pops and such were heard from land. maybe even use a boroscope if you can borrow one to check out the cylynders.

good luck.

Don't mess with it if it is still under warranty..
Let Merc handle it.

Chris

Thanks for the info. Let you know how it turns out. Thought I would ask if anyone has had problems hope not these motors are in super tight first one done without drive lines so its a major undertaking the get them in let alone work on them.