The lower on my Bravo 1 is plugged up, what would be the best way to get this unplugged? Can this even be done?

plugged up as in welded shut? Or plugged with debris?

If it was just welded up, drill it out. It is just aluminum and will drill out pretty easily. Try not to screw anything up in doing so.

If it is debris, try to break it up with a piece of metal rod/screwdriver/whatever will fit, then blow compressed air down the water inlet from the top.

Folks often have success with a drill bit either fastened into vice grips or a slow-speed/hand drill. This is great for getting wood splinters and other similar crap out of the speedometer pickup hole and LWP holes.

Thanks guy's I bought the boat and when we winterized I noticed the LWP were not leaking water on the one side. So seeing the driver coolers were plugged with wood makes sense.