Replacement Upper Unit Mercruiser R MR Alpha One Old Style 104-01B
Replacement Upper Unit for Mercruiser R, MR, Alpha One. 1.81 Ratio
- Comes with an [old style] 8-1/8" input yoke.
- This drive is generally used on older inline 6 and 4 cylinder engines.
- For Alpha One Gen I Sterndrives 1972-1990.
- 3 Year Manufacturer's Warranty
- Model: 470
- Year Range: 1976-1982
- Serial Range: 4208730-6225576
- Model: 485
- Year Range: 1980-1982
- Serial Range: 4893835 and up
Item is subject to a 20% restocking fee (Boat Covers, Bimini Tops, Outdrives, Drop Ship Items and Special Order Parts)!
How to Install Sterndrive Engineering Short Yoke
- First, determine the length of your yoke. Newer styles are 9-9/16" and older styles are 8-1/8". Remove the clips that hold the u-joint together. You can use a screwdriver to push on it to make removing the slips easier. You may need to use the screwdriver on both sides.
- After the clips are out, use a hammer to tap the u-joint in one direction until you can remove the cup on the opposite side. Use a suitable socket so you do not hit the yoke with the hammer. If the seal is stuck to the u-joint, use a small pick or screwdriver to remove it.
- Using a socket of the appropriate size, pound the u-joint in the other direction. The purpose of the socket is so that you don't hit the u-joint post with a hammer. The socket should fit over the post and contact the body of the u-joint before the post.
- With the yoke out of the way, you can start reassembly. Install both u-joint clips and the u-joint and check to make sure they rotate smoothly. If everything looks good, take them off. If you're experiencing rough rotation, your u-joint will most likely need to be replaced.
- Install the yoke over the posts of the u-joint then insert both u-joint clips while centering the yoke.
- Tap the u-joint together. You may be able to tap one side in all the way and put the clip in, or you may need to tap each side in a little bit at a time.
- With both clips in, turn the yoke and see if it turns okay. If it is stiff, try hitting the opposite side.
- You will need to grease the u-joints using a grease gun and grease that is approved for u-joints.
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