Center Main Bearing Johnson Evinrude 40-75hp 1972-03 Rpl; 310433

The inner diameter of all sleeves are undersized and must be finished to desired size. Please read the information below before you order.
For your information: The sleeves are not cut to standard size because of the installation process of the cylinder sleeve. The cylinder sleeve is an interference fit in the block of .004-.005 inches. In order to install a cylinder sleeve, the block must be heated to 400 Degrees for 1 hour. Then you can install the sleeve and line up the porting. Allow the block to cool to the touch, and then you must machine the sleeve to the desired size. Also the surface of the sleeve will have to be machined to match the surface of the cylinder block. You can also Install the sleeve with a press (cooling the sleeve first in a freezer for about 1 hour). Make sure you line up the porting and the follow the same procedure to finish to the desired size. Because the sleeve is an interference fit in the block, when the block is heated and then cooled the sleeve will not remain completely round. This is why the cylinder sleeve is machined under the standard size.