am I missing something?

[rotodd]

I am having problems with my 1987 Mariner 45 pumping water. I have a new impeller, upper and lower housings. My question is, the top housing where the water tube goes into, is there some type of seal or washer that goes into the top of the housing? Or does the housing just narrow done onto the water tube and create a seal. I am not getting water up to the engine. I took off the cover plates and made sure they are not clogged. I can blow air up the water tube and have no restriction. I feel my pump is not pumping water. what else could be my problem?

 

[racerone]

Well, if the drive key is properly installed it is nearly impossible for the pump to NOT work.----They are that simple !!-----------The big question for you is about your test method.----Is the water in your test tank at least 6" above the pump, yes or no ?

 

[rotodd]

I was trying with muffs on. I will check the key to make sure it is in place. Thanks

 

[wn6ngp]

I know that they make a big deal out of not using full water pressure on those muffs, but I have found that I have to have at least ~40psi otherwise the water doesn't get up to the top and the motor will overheat. I use a pressure restrictor for RV's for use at RV parks of uncertain water pressure.

 

[tommarvin]

Again, is the water six inchs above the water pump or pump wont pump, never use muffs not enough water..
We made a wood box as deep as we could to run the motors in so they get all the water they can pump.
Are you sure the impeller vanes are going the correct direction, looking down the driveshaft turns clockwise.on our 115hp, you can look at the flywheel pull start direction too.
Is water coming out the indicator stream hole?

 

[Texas Prowler]

I wonder if the vanes are facing the correct direction. Was the last impeller deteriorated/ broken in bits?

 

[rotodd]

Yes, the last impeller was bad. This impeller was replaced this spring. It worked fine a couple times out. The last time, it was working fine , then suddenly, my overheat alarm went off, when I looked the telltale was not putting out water. I turned the engine off and let it sit awhile. Started again and the was cooling ok. Assumed I had impeller pieces floating in the engine. Took the side cover and back cover off and found pieces inside. put it back together and not getting anything out of the telltale. The telltale is not plugged, I checked it when it was apart. Looked at the impeller, the vanes are going the right direction and the key was in place. Don't know what to check next. It is 27 degrees and snowing today. Don't want to go to the lake or try it with muffs on.

 

[Mercurylips]

Possible that the water tube is not positioned into the pump outlet correctly? Happens to me when I put my Mercury lower back on after changing seals out.

 

[rotodd]

I made sure the water tube is in the pump outlet. Which brings me back to my original question. Should there be a seal of some kind in the top of the pump outlet?

 

[racerone]

Did you install a water pump kit ?------Was there a seal in the old housing ?-----A seal is shown in the parts book !

 

[Texas Prowler]

Yes, the last impeller was bad. This impeller was replaced this spring. It worked fine a couple times out. The last time, it was working fine , then suddenly, my overheat alarm went off, when I looked the telltale was not putting out water. I turned the engine off and let it sit awhile. Started again and the was cooling ok. Assumed I had impeller pieces floating in the engine. Took the side cover and back cover off and found pieces inside. put it back together and not getting anything out of the telltale. The telltale is not plugged, I checked it when it was apart. Looked at the impeller, the vanes are going the right direction and the key was in place. Don't know what to check next. It is 27 degrees and snowing today. Don't want to go to the lake or try it with muffs on.

You likely still have bits and pieces in the block hindering water flow.

 

[Mercurylips]

rotodd. I am not familiar with your motor. Mine had a seal that came with the pump kit but my motor didn't use one so it is not on it. My water tube is fairly rigid in the motor housing so when tightening up the lower unit it makes a good seal with no help, just a taper in the pump housing. I also tried air but found that a good tight nozzle on the garden hose and some work with some flexible wire took care of my tell tail volume. I started out with just wire and then went to the hose. After I put my lower on correctly the stream looked good. It was weak before I "rodded and flushed", with the lower on correctly. Texas Prowler has the same line of reasoning on this as I do.

 

[rotodd]

Ok, I'm back. Been thinking about all of your suggestions. Let me say, I am obviously not a boat mechanic. I am a toolmaker, so I have some mechanical ability. That being said, I see no reason the pump should not be pumping and I see no reason the engine be plugged. I took the two covers off and got a lot of pieces of old impellers out. I took an air nozzle with a rubber tip, to seal around the tube, and blew air up the water tube. There did not seem to be any restrictions, the air flowed through the entire system. Now, racerone and tommarvin, you might be onto something. If my muffs do not seal around the lower unit well enough, the water might not get up to the pump. Currently it is 21 degrees and snowing here in northeastern Indiana. When I get a warm day I will put the lower unit back on and put it in a barrel to make sure I get enough water to the pump. Thanks everyone for your help.