no water circulating out

Not great with outboards and need some help. I have a late 70's mercury 4hp thunderbolt outboard. Bought it a week ago and it runs great except for (1) thing. While its running I noticed that no water is being pushed out the fresh water port (I guess you would call it that), but there is air being pushed out the strong enough for me to feel it on my hand, so the water pump must be working right? So no water coming out, but air yes, so I thought there must be a blockage. So I hooked up a hose to the bottom and turned the hose on (engine off) and water was pushed up and out the fresh water port. Any one have any ideas why water isnt being pushed out. Much appreciated, thanks everyone. Detcuse

Re: no water circulating out

When the air was coming through the port, was the motor in the water on or on the hose? Have you tried turning it on since you hooked the hose up and had water flowing to see if you may have washed away any blockage (be careful, it only takes a minute to ruin the cooling system)? The air coming out sounds very strange since any typical blockages would obstruct all flow through the port.

Re: no water circulating out

I have the same problem with a 9.9 recently purchased used. I hooked it up with the intake submerged in a barrel of water and all I get is air out of the indicator hole. The guy I bought it from had it hooked up the same way and there was a trickle of water coming out then. The manual says that there might be a thermostat? I checked for obstructions and found none. I haven't tried to force water through the pump.

Re: no water circulating out

Yes I did have the outboard in a 50 gallon drum of water when just the air was coming out. Do all outboards have thermostats? And if so, would that even make a difference because I had the water being pushed through the system from the bottom up with the hose? Thanks again for all the replies.. hope i get this fixed soon so I can enjoy the motor for the rest of our short summers.

Re: no water circulating out

Bump...like to know this one as well as I have same issue on my 200 hp. No water but do feel some air pressure. I have a feeling its the impellar from running without water hooked up even though it was only for a short period of time.

Re: no water circulating out

Gent's I need your help!!! I have 100HP 1991 4 cylinder Mariner that does not pee. I have pulled out the thermostat and replaced the impeller and still no pee. I even pulled out the pop-it valve and ran it with out it. Still no pee. The motor runs cool on the muffs and idles all day without getting hot, but no pee ever comes out. I did get it to pee out the little hole in the pop-it valve, thermostat cover when they were not in, but the cover was on. So what gives????

Re: no water circulating out

TonyD1976 said:

Bump...like to know this one as well as I have same issue on my 200 hp. No water but do feel some air pressure. I have a feeling its the impellar from running without water hooked up even though it was only for a short period of time.

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I replaced my impeller and have water...mine was shredded!