My BF50A, frame serial BAZL-3008546, has developed a crack on the lower unit casting which extends from the vicinity of the prop forward toward the sealed gear pod. It appears that a metal part inserted into the lower unit, a part which apparently supports the prop-shaft, has corroded against the inner side of the lower-unit casting, causing the casting to crack. Have others of you had this problem? What can be done to stop the corrosion and repair the crack?

I had the exact same problem, my advice would find someone with a tig welder and weld it up.

In my case I had line in my prop seal which tore up the rubber causing water to get in the lower unit. Thus i had to pull the bearing carrier to change the seals. There is a metal retaining ring inside the prop followed my a threaded on nut. Long story short while trying to get the nut out the crack had grew to a U, which broke off the lower unit. Luckily the piece that broke off went back in the lower unit like a puzzle piece and we welded it up. Hope this helps.