i havent done many water pumps
i havent done many water pumps but i do have the ns25c3 and i just put a pump on it last week. Not an expert here but it is one of the easier ones i have ever done. the shift lever halfway up the shaft on mine is exposed and i removed one of the roll pins to disassemble it. removed the 4 bolts on the lower unit plus 1 bolt on the front side and the unit slid right out. removed the little housing at the base of the shaft that houses the impeller. TAKE NOTE OF WHICH WAY THE FINS POINT!!! Yeah i made that mistake and got to do mine twice! anyway reverse all that and shes done. Helps if you have another pair of hands to manhandle the lower unit but can still be done by yourself fairly easy. Hope this helps a little.