Water pump that will not prime

Rebel

Well-known member
Joined
Sep 28, 2009
Messages
90
Fluid Motion Model
C-248 C
Hull Identification Number
FMLT2565K708
Vessel Name
JOHN'S FOLLY (2008)
While trying to winterize my R25 I ran the water pump to empty the water tank. Not sure what happened but after I had ran the tank empty and then added the pink stuff the pump would not prime and circulate the stuff through the pipes. I then filled the water tank back up to see if that would help get the pump to prime but still no luck. I ran the pump for an extended time, at least 20 minutes, and still was not able to get the pump to pime. Does anyone have an idea on what to do next? Your thoughts would be appreciated.
John Turner
 
The same thing happened to me last year. I never could get the pump to pick up the pink stuff. After talking to Andrew the following spring we deduced that the pump picked up debris from the tank. I eventually had to replace the pump. I now have a filter installed between the tank and pump and have had no problems.
 
Having replaced these Johnson fresh water pumps twice, it is my experience that they are self-priming if the hose is not obstructed. If your situation was on the Laurie Ann, I would run the pump while moving or wiggling the uptake hose from the tank. There could be a physical obstruction in the hose, or it is kinked or perhaps there is a air bubble between the pump and the tank.

If you did not know, the fresh water pump is under the floor at the pilot's station and is accessed by removing the cabin heater grill, pulling that up and setting on the pilot's floor, and the pump is either on the vertical wall or hung upside down on the pilot's floor. The hoses going to and from the water tank are all right there. It is also a good time to check all the hose clamps that you might find there.

If you have to replace that pump, it is a straightforward operation.
 
Heres what I do when I loose the prime on the R21. I add pressure to the system. Turn on the pump open the faucet and either add air or water to the fill port wrap a rag or plastic bag around the hose so it holds pressure. With the water turned on full and using your third hand to plug the vent you should after a few seconds hear a change in the sound of the pump. Do not put too much pressure in the tank as that may damage it and if you have a hose clamp that is loose it will show up with water everywhere. Relieve the pressure by removing fingers off the vent or you will have a water gusher when you pull the hose out. Running the pump dry will also damage it and I would have doubts on a pump run for twenty minutes. I loose prime after a long road trip once in a while and this works good. After pumping the water out of the tanks for the winter I listen to the pump change its noise and shut it off before adding the pink and then run the pink through the system till it turns color. The bigger the system the more pink antifreeze is needed but that is all there is to it. Compressed air works too but water is usually easier to get near a boat. I do a reverse in the spring by flushing the antifreeze out with lots of water. Again listening to the sound of the pump. Over the winter for water I pack it in a jug and usually just buy bottled water. The antifreeze must be for rv use or you may surely die using automotive stuff.
Andrew might publish a note to be part of a new boat package on how to prime the pump. Thats all there is to it.
Good Luck Bob Heselberg in Eatonville Wa where we got our first freeze of the season last night.
 
I used to have this problem on my old boat. I would get an air pocket on the exit side of the pump. I would loosen the hose and turn on the pump until I got the water to flow then re-clamp the hose. Worked every time.

Doug K.
Nauti Dream
 
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