jay_merrill
Vice Admiral
- Joined
- Dec 5, 2007
- Messages
- 5,653
Re: Near Disaster
I found one of the sheared pieces of the swivel bracket eyes in the boat today. There wasn't much grease in it, which is my bad, but the bracket was not frozen at all - it tilted up with no effort other than what would be expected, given the weight of the motor.
What I noticed in particular, is that this casting looks like it was poorly designed. If you look at the piece, it is obvious that the grease channels result in a reduction of material to resist shearing from excessive loads. It just looks to me like there are built in weak spots.
I also noticed a brown spot just under one of the grease channels - see the bottom right corner in the photo, below. This bracket is cast aluminum, so I don't believe that is corrosion (aluminum corrosion is normally white), but it does indicate that there was a void in that location. It appears that something was able to seep into a crack in the piece, thus discoloring it.
After talking with my local BRP/OMC shop, and surfing shop.evinrude.com, I believe that this swivel bracket assembly was also used on OMC triples prior to 1972. This means that the 1968 & 1969 55hp motors, and the 1970 & 1971 60hp motors, will have the same potential for breakage. There are also other OMC motors of this vintage that have a similarly designed swivel bracket. For example, the 1972 JonnyRude 50hp motors have different transom brackets (with screw type clamps), but the swivel bracket is similar to the 65hp piece ... including the grease channels in the eyes.
Just as a "safety bulletin" to my fellow iboaters, if you have any one of these motors, I recommend caution in this regard. Frankly, inspecting the brackets for existing cracks would be difficult, without putting the motor on a hoist and removing the tilting bolt, but whatever you can check, I would.
Thanks to all for your kind comments. I hope I have returned the favor by providing a little info that might prepare others for the possibility of this happening with their own motors.
I found one of the sheared pieces of the swivel bracket eyes in the boat today. There wasn't much grease in it, which is my bad, but the bracket was not frozen at all - it tilted up with no effort other than what would be expected, given the weight of the motor.
What I noticed in particular, is that this casting looks like it was poorly designed. If you look at the piece, it is obvious that the grease channels result in a reduction of material to resist shearing from excessive loads. It just looks to me like there are built in weak spots.
I also noticed a brown spot just under one of the grease channels - see the bottom right corner in the photo, below. This bracket is cast aluminum, so I don't believe that is corrosion (aluminum corrosion is normally white), but it does indicate that there was a void in that location. It appears that something was able to seep into a crack in the piece, thus discoloring it.
After talking with my local BRP/OMC shop, and surfing shop.evinrude.com, I believe that this swivel bracket assembly was also used on OMC triples prior to 1972. This means that the 1968 & 1969 55hp motors, and the 1970 & 1971 60hp motors, will have the same potential for breakage. There are also other OMC motors of this vintage that have a similarly designed swivel bracket. For example, the 1972 JonnyRude 50hp motors have different transom brackets (with screw type clamps), but the swivel bracket is similar to the 65hp piece ... including the grease channels in the eyes.
Just as a "safety bulletin" to my fellow iboaters, if you have any one of these motors, I recommend caution in this regard. Frankly, inspecting the brackets for existing cracks would be difficult, without putting the motor on a hoist and removing the tilting bolt, but whatever you can check, I would.
Thanks to all for your kind comments. I hope I have returned the favor by providing a little info that might prepare others for the possibility of this happening with their own motors.
