SuperYooper
Cadet
- Joined
- May 8, 2011
- Messages
- 26
I have 2 mercury 650 outboards and I am pretty sure they are both from 1971. One engine works great with a banged up lower unit. I want to use the lower unit from the other engine but am not sure if it will work. I do not want to try it and ruin the good engine so I figured I would post the information I know and photos and see what you guys/gals think.
The numbers on the lower units are as follows:
Bad unit: 1623-4021
Good unit: 1623-2022
I have not been able to find what they mean or how they are related. Since the first four digits are the same, does that mean they can be interchanged, or does the last four numbers being different mean they can't?
The basic measurements are the same such as the size of the unit, the number of teeth and length of the shaft, the length of the water pipe, and number of teeth and length of the gear pin.
There are some differences though:
As you can see, the left shaft has a pin sticking out of the top and the other doesn't. The shaft on the right has a spot just below the teeth for an O-ring and the one on the left doesn't. Big deal?
This is a view over the top where you can see they are molded a bit different, but the bolt positions are the same.
This I don't think is a huge concern, but I think the prop rod is a bit bigger (I have a prop for both) on the left, but the back plate (I have no idea what these things are really called) is molded into the gear box as opposed to the one on the right where it is removable (it is not on in the picutre)
This shows the gear pin and the impeller case appear to be an exact match.
If anybody has any suggestions on wheather these two could interchange please let me know. Thanks for your time!!
The numbers on the lower units are as follows:
Bad unit: 1623-4021
Good unit: 1623-2022
I have not been able to find what they mean or how they are related. Since the first four digits are the same, does that mean they can be interchanged, or does the last four numbers being different mean they can't?
The basic measurements are the same such as the size of the unit, the number of teeth and length of the shaft, the length of the water pipe, and number of teeth and length of the gear pin.
There are some differences though:
As you can see, the left shaft has a pin sticking out of the top and the other doesn't. The shaft on the right has a spot just below the teeth for an O-ring and the one on the left doesn't. Big deal?
This is a view over the top where you can see they are molded a bit different, but the bolt positions are the same.
This I don't think is a huge concern, but I think the prop rod is a bit bigger (I have a prop for both) on the left, but the back plate (I have no idea what these things are really called) is molded into the gear box as opposed to the one on the right where it is removable (it is not on in the picutre)
This shows the gear pin and the impeller case appear to be an exact match.
If anybody has any suggestions on wheather these two could interchange please let me know. Thanks for your time!!