Looking at a 2012 low hour 5500 black death on a 1854 excel f4. The Excel is not my first choice in a boat but this rig is turn key ready and close to my home. I don't know much about the motors and looking for some help

5500 BD should have most of BPS parts already in it and on it. Some folks don't care for the twin carbs, but if you know how to keep them adjusted they perform pretty well. We have the MB 7000 on a Excel F4 1851 and it runs hard and breaks ice really well. Have had no issues with boat or motor.

I don't know much about the twin carbs but my other question I have is there a way to verify the hull thickness. The guy said it was a.125 hull but I also heard there are more .100 hulls up here in the north

A micrometer or a set of calipers should work for checking hull thickness.

Not sure bout '12 but it may say on a welded on tag on the starboard side under the hull number and ID tag. I know they do that with the newer ones.

Is there anything specific I should look for on this motor when I look at it?

First thing I would do with a used motor is check compression