1983 Mercury 50hp not pumping water but still pumping air?

[tshelton1]

I recently purchased a boat and have been going through it trying to get it running good. I have posted a few questions on here and have got good responses. I have the motor running great but when I started it hooked to the muffs the other day it did not pump water just air/steam. I shut it off immediately and took the lower unit off to inspect the water pump. The impeller was nicked up pretty bad but intact I used the hose to spray up the outlet tube and had water coming out just fine.I put it back together and started it up and had water coming out just fine. I let it run for maybe 30 seconds and revved it up and down and turned it off.

I took it out last night and sitting at the dock it took a few seconds but started pumping water. I drove around the dock area and the boat ran great. I was watching the water outlet and I saw it to start to sputter so I turned the boat toward the dock and then it stopped pumping water all together so I killed the motor and drifted slowly back to the dock. It was pumping air/steam out of the outlet. I went ahead and ordered the water pump kit and impeller. As for the pumping of air I still do not have a clue why it would still pump air but not water. Is it normal for it to still pump air out if the impeller or pump are bad? It may just be a little air/steam from the heat but it seamed to come out pretty good. Anybody ever have this happen to them?

 

[Sea Rider]

Is this motor used on salt or fresh water. ? If on salt run Salt Away product through motor while revs at fast idle on a barrel for at least 15 minutes to flush, lessen internal salt layers, crusts formations after have installed a new water pump kit.

Is thermostat in good working order, if rusted, extremely salted install a new one including thermo gasket, motor will work much better along new water pump kit.

Happy Boating