transom plate

If it is a small motor (25 HP or less) on a boat with a plywood core transom, you may want to consider drilling the transom with sharp bit and coating inside the holes (drill 1/16 oversize) with epoxy. The most common place for the aluminum is on the inside of the boat and usually results from a soft area where the clamps go. A better long term solution might be epoxy and biaxial glass. I wouldn't run the engine without bolts through the transom. At least use a safety chain to secure the engine. It won't save someone from an injury by the flying prop if it becomes free of the boat, but will save the engine from a complete dunking.

Frank_S

 

Bolt that sucker down! I learned my lesson when I hit an underwater log and it almost took the motor off. If it's a wood transom like most just do like frank said and drill it then coat the inside of the holes with epoxy (Q-tip works well for this). If you are still worried about water intrusion then use some silicone or 5200 in the holes when you bolted it. Thats how I did it.