I have a small long shaft 5hp mariner but cannot get any information on year. The number as on motor housing is 6E3-L-423159 I am told by my local boat shop that this is Model 7005225 with a serial # of 423159. They could not however find the year. I want to order a manual as I will be attempting to replace water pump soon. Also I have valve opening at bottom of shaft labeled "wash" what is this for. 