I'm changing the two bottom through Bolts (Carriage Type) on my Bravo One Transom mount as they have desintegrated over time and saltwater. My question is, are these some different metal? They are not magnetic and light as a feather. I was going to change them with galvanized or Cad plated but I think they might serve some pupose with the stock material. What are they? Do I need to put the original type back in? Thanks.

They are aluminum, anything else will cause the housing to corrode. Must be an early transom, newer ones use studs.

I did mine last year and went back with stock, I am not sure about the material but it drilled like aluminum (mine did not want to come out). Good question though.

It's a 1989. Thanks, how about stainless?

Dissimiliar metals, it will corrode the aluminum and make the paint bubble off.

Just get the ones that merc has, can't be too expensive.

this is great advice

the bolts come in a kit with the rubber o rings and zincs they are about 35.00 for the kit

Be careful not to overtighten and squeeze the o-rings out. No zincs on these bolts on a bravo. They have a carriage bolt type head.

Found out they're made of aluminum. Mine's an 89 and they only had the round heads on the outside with no Zinc attachment stud so the bolts gave there lives instead. All the replacements are aluminum as well and have the studs for the zincs on the outside. Got 'em, Thanks. Yep $35.00