I havea 1984 merc 35 hp that the reverse doest work on, I was told that there is a cogged plastic washer that is the problem in the lower unit behind the prop, that needs to be replaced, I removed the old one but cannot get the new one on, it seems like the bearing carrier is not on all the way and I cannot get it to tighten up ,it just seems to spin, is there a trick to tightning the carrier or am I missing something??? Help