Is it very hard to remove the lower unit from a 70 horse Mercury outboard?

Question

I need to replace the cooling pump.

Answer 1

The lower unit is fairly easy to remove. Make sure you put the engine in forward gear. Make sure the shift shaft is disconnected (you might have a splined shaft so you dont need to disconnect it). Remove the trim tab to access the bolt above it, remove the front bolts (nuts), and the rear nuts. Disconnect the speedo pick up and remove the lower unit. the impellar housing should have three nuts on it holding it down. When the housing is off if you notice blades missing fromt he impellar, locate and remove all the pieces before putting it back together. Also make sure the housing is not groved or melted, if it is replace it. A water pump repair kit will come with every thing (housing, impellar, key and gaskets). The service manuals will tell you to use a new impellar key, however you can reuse the old one if you are just replacing the impellar. Line the key up install the impellar over the key. Lube the housing witha light coat of lube (I use greese, other people might say that regular grease may harm the impellar but I have never seen it). Rotate the drive shaft in the direction the engine turns will running while pushing down on the housing. When putting the lower unit back on turn the prop to realign the drive shaft splines to the crank (this is why you put it in gear). MAke sure the water tube, shift shaft are lined up before bolting it back on. It is a good idea to make sure the speedo tube is reconnected also. (that saves a darn it). If I new exactly what engine you had (year wise) I coule be a little more detailed. I also hope that Mercman sees I added his commets from last time.

Answer 2

It helps to have the manual. Do not do this job in the water Now on land, the lower unit is held on with 6 or 8 stainless socket head cap screws and the water pump is at the top of the part you pull down and off just be carefull to get the rubber blades bent the direction of the old pumps impeller and grease and fill the lower unit with the proper lube good time to change the lower unit oil too. Easy about 2 hours first timer