Hi,
 
The perkins 4154 has 2 water pumps: a Sea water pump and a Fresh water pump.
Check the parts manual:   
http://www.kp44.org/ftp/Perkins_4-154_Parts_Manual.pdf
 
the Sea water pump is a Jabsco NA 003428 and is a suction pump with a rubberised? impeller!
 
The fresh water pump is a bronze recirculating pump and it has a metal impeller.
 
They are not to be mixed or confused. The Sea water pump must suck the sea water through a filter which must be set above the waterline.
 
See the Vetus instructions for installation of their sea water filter. I almost lost my boat because a previous owner decided to lower this filter because the impeller on the pump was defective. By lowering the filter you allow a siphon to be created, even if you have a anti-siphon valve!
 
BTW, when you replace the impeller on the Sea water pump, you must also try to locate in the circuit, usually at the heat exchanger, the parts that may have broken off from the impeller.
 
The fresh water pump, unless extremely corroded will simply drive the recirculation liquid- usually containing an anticorosion and antifreezing pruduct- as long as there is enough liquid in the motor.
 
I always have aboard, in working order or new pumps, and even if my boat is a sailboat, would not consider blue water sailing without.
 
I have no relation with the following store, but Sheri from Trans Atlanctic diesel, has given me the best service for parts for my Perkin, as well in Europe as in the Caribean.
 
Serge, V/Opera
Mango #51

 

De : Andy <allezaubon@...>

À : amelyachtowners@...
Envoyé le : lundi 4 juin 2012 5h40
Objet : [Amel] salt water pump


 
Dear all, we are the new owners of an Amel Maramu. We are hoping to get some advice on the cause of a problem with a saltwater centrifugal pump for a Perkins 4154 engine and what pump we should replace it with ( another centrifugal, impeller ??)
we have just completed a 1500nm passage during which our centrifugal pump repeatedly stopped working. we were able to solve this initially by opening the filter, which then immediately filled, due to the water pressure from the sea cock, when full closing. when this tactic no longer worked , we resorted to self priming the pump, which kept her going for a few more days, then eventually the pump would not draw at all. we changed to our freshwater pump a Shurflo diaphragm pump, which operated for the next 6 days problem free, as we motorsailed home. we did take the old centrifugal pump apart and the ends of the blades did seem to be slightly damaged which would effect the draw and flow but not enough, methinks to shut it down completely. I will lower the salt water filter to be below the waterline, however am not sure that the problem lies solely with the pump and if I should replace it with another centrifugal pump, or go for an impeller

pump............which also have their own related issues. Any advice will be much appreciated. Kindest regards Andy

Andy

Thanks for all your feedback - we have used Trans Atlantic for spares previously and also experienced excellent service. Serge will reconsider dropping the filter to below the waterline !! Kindest regards Andy
PS We are located in Hong Kong and have Hull # 75