Cant get my new raw water pump to pump. My engine a yanmar 3gmf turning clockwise starts great but no raw water discharge. I removed the discharge hose from the heat exchanger while running no water present. I removed the hose leadi g into the pump from the strainer an have water on a slow steady stream. The impeller is new but did overheat twice . All looks good upon inspection. This pump appears to be able to pump both directions as indicated with arroes on tne pump impeller plate. I am puzzled as to why no water discharge. Any ideas out there would be appreciated greatly. I am stumped.
engine cooling pump problem
- Thread starter bryan crites
- Start date
If the pump itself overheated, I would not trust the impeller at all. Some impellers can lose grip between the rubber and the shaft.. so the shaft turns but the impeller does not. When you re-assemble with the new impeller, use a grease inside the housing like this http://www.acehardware.com/product/index.jsp?productId=3506761
Easiest to pull the whole pump to do the work. check by hand turning after you've gotten it off .. make sure the hose from the strainer, through the sea-cock and out the thru-hull is free and clear. You can put a garden hose into the end that you remove from the strainer and blow out the thru-hull (do not pressure through the heat exchanger with a garden hose); should be clear. Make sure there are no air leaks in the strainer top where the screen can be removed. Yes the pump can work in either direction, but the rotation has to be reversed to make it pump right to left instead of left to right when looking aft at the pulley.
Easiest to pull the whole pump to do the work. check by hand turning after you've gotten it off .. make sure the hose from the strainer, through the sea-cock and out the thru-hull is free and clear. You can put a garden hose into the end that you remove from the strainer and blow out the thru-hull (do not pressure through the heat exchanger with a garden hose); should be clear. Make sure there are no air leaks in the strainer top where the screen can be removed. Yes the pump can work in either direction, but the rotation has to be reversed to make it pump right to left instead of left to right when looking aft at the pulley.
Re: pump
No I have no water coming out of the pump a decent flow to the pump though. The impeller turns by hand when I hav the pump in my hand . Is the pump designed for the water to flow over the inside top of the pump or through the lower side of the pump where the brass insert is an the drain screw? I also have seen a rotate kit for the pump mounting for easier impeller access.
No I have no water coming out of the pump a decent flow to the pump though. The impeller turns by hand when I hav the pump in my hand . Is the pump designed for the water to flow over the inside top of the pump or through the lower side of the pump where the brass insert is an the drain screw? I also have seen a rotate kit for the pump mounting for easier impeller access.
Pump flow is in at top left (looking aft), up and around/over the top then out at right side again looking aft. This assumes rotation is clockwise looking aft. The insert is on the bottom and is held in place by the little screw through the case. Usually, when ya have one that won't pump and has a new impeller, the impeller diameter is too small, or there is too much side clearance between impeller side and case/cover (could be caused by too thick a gasket under the cover) or air leaking in.
EDIT: If the cover plate and case bottom have deep scour marks or the perimeter of the case has scour marks from sand/grit being dragged by the impeller, they can sometimes be deep enough to allow enough water to bypass so the pump does not pump well.
EDIT: If the cover plate and case bottom have deep scour marks or the perimeter of the case has scour marks from sand/grit being dragged by the impeller, they can sometimes be deep enough to allow enough water to bypass so the pump does not pump well.
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Been there
I have the same boat with the same engine and had the same problem. After two weeks of head scratching and completely rebuilding the water pump I still had no water coming out of the discharge. So, I started at the pump disconnecting hoses to see if water flowed from the pump. I got all way to the mixing elbow and discovered it was clogged with carbon. I bet you have the same problem. I used a screwdriver to clear it.
I have the same boat with the same engine and had the same problem. After two weeks of head scratching and completely rebuilding the water pump I still had no water coming out of the discharge. So, I started at the pump disconnecting hoses to see if water flowed from the pump. I got all way to the mixing elbow and discovered it was clogged with carbon. I bet you have the same problem. I used a screwdriver to clear it.