I am doing a rebuild of the lower unit gearcase.<br /><br />The gear set I ordered came with pretty good break-in instructions, but did not say anything about changing the gearcase oil (for example: after x hours).<br /><br />Do I just leave the oil in until the regular interval (end of season)?<br /><br />Any recommendations?<br /><br />1984 Evinrude 150hp.