hey that's a 1994 motor"ER" means 94 yr and "EX" means electric Start with 25" shaft. Here's the manual you will want and the searay guy is great to deal with i've bought several items from him. link below
http://cgi.ebay.com/1994-150-150c-17...QQcmdZViewItem
You should also buy a parts catalog so when you need parts or part numbers, plus to see if or what parts from other years will fit and work on your motor. here's one on ebay as well. this guy is great to deal with too i've got at least 20 or so different ones from him for different motors i've fixed or had. Link below
http://cgi.ebay.com/ebaymotors/1994-...spagenameZWD1V