Something Chomped on My Cavitation Plate
Many lower units of 4-cylinder Mercs from the late 1950s and early 1960s have a piece missing from the cavitation plate. Ed is pretty sure these are caused by someone hitting it directly with a hammer or using a piece of wood while trying to drop the lower unit.
The reason could be the 4th bolt holding the lower unit to the midsection was not removed. This bolt with its hole for a 5/16-inch Allen wrench is "hidden" up the lower exhaust port. Perhaps some amatuer mechanic thought the LU just needed some encouragement.
Another reason (to which Ed can personally testify) concerns the two nuts on the sides of the LU. These can be loosened but not totally removed until the LU is dropped down somewhat. Then there is room to remove them completely. If you forget to do this, it might seem that the LU needs a gentle tap on a 1x2 with a hammer. Even a gentle tap can break loose a piece of the cavitation plate!
Honest, Ed only did one of these.
