I am resealing the lower unit on a 15 hp low profile Johnson. I pulled the brass shift rod bushing and replaced the seal and that nylon washer. I reinserted the bushing and drove it in and it stays about a 16th or a little less from being flush. I think it may have been flush before but I really cant remember. It seems to hold water out of the gear case when i tested it. If anyone can shed some light I thank you in advance.