Merc "a" rusted bolt

[crankbearing]

Hey All,

I have a question and I am a little concerned, I took an j/a merc apart the other day and the top crankcase bolt inside the intake was rusted badly. I know this motor has never been under water and it only has two seasons on it.. The hole in the block is open to the elements but so are the others so this should have no affect. I have done a few of these and this is the only one I have seen like this.

Anyone else come across this ?

Regards,