I have a 1990 85hp Suzuki outboard and I recently got what looks to be a stress crack in the lower unit gear housing.  The crack is right where the prop meets the housing and is about an inch long.  There are two hairline cracks that branch off from the main crack.  What causes a crack in the gear housing and how do I fix it?

What causes a crack in the gear housing?

To many things to list

How do I fix it?

Replace it

Theres a product called JB Weld get the industrail one not the hobby stuff. If your crack has not went into the oil area I would drill a small hole were the crack ends and use this JB Weld it's good stuff. If it has went into the oil area it will still work unless it's in the bearing areas.

Garnet

If your looking for a lower unit. I have one for sale. Its off of a mid to late 80's 85hp suzuki. Bought it last year to replace mine on my 75 suzuki, (75 and 85 are the same) never needed it. still the the package it was shipped to me in.