water pump not pulling any water on 5.7l volvo penta gsi pefs

[Jhilton0816]

i removed the impellar housing to check to see if i needed to replace the impellar, it was good, i guess the place that winterized it for me changed the impellar, i also changed my tstat and cleaned up the housing a bit, and found a bunch of big impellar fins probably from a previous impellar. i cleaned up the old gasket put a new gasket on and replaced t stat and put the housing back in place and connected hoses, i start the engine and however now it over heats.... i pull the hoses and it looks like no water was being moved. i unook the top hose that goes to the t stat housing and started the engine and sure enough no water was coming out of output of the impellar housing.... so i take it off and turn the impellar around incase.... no change, i then took it back off again to see if the little sprocket that goes through the impellar moves when engine is running... sure enough its moving. i then put the impellar and housing back the way it was and put it back on the water pump... i then started the engine and wanted to make sure the impellar was moving so i put a flad had lightly in the top output port and sure enough the impellar fins were hitting the flat head due to it moving.... my issue now is why isnt any water coming out???? mind you all the hoses were emptied prior cause i pulled them off to replace the thermostat..... so they are all still pretty much dry.... but i need help... do i really need to replace the water pump? if i do which part do i need exactly, and how much is it? i only run the boat in lakes if that helps

 

[gbeltran]

Are you supplying water with a hose? Or was this with the boat in the lake?

 

[Jhilton0816]

I tried hose and then I put it in a big tub of water making sure all holes on the stern drive were underwater

 

[gbeltran]

Put the hose back on. Putting it in a bucket won't work at all. The water level of a bucket is not high enough to allow the pump to prime. If you have a problem with it in the hose then you have an issue between the pickup and the pump. As for the hose there is a specific adapter for the SX drive, the cups are rectangular.

 

[Jhilton0816]

The whole bottom portion is underwater in the bucket, the 3 holes(Intake) are 8 inches below water so it replicates being in a lake, but still no water is being sucked up to the impeller even with the round ear muffs

 

[Jhilton0816]

Unless I'm misunderstanding you in sure the big tub aware should work the same

 

[dypcdiver]

Have you got the hoses the right way round on the pump? They are easy to mix up, the bottom hose goes to the thermostat housing.

 

[Scott Danforth]

you should be running on muffs when on land.

there is no way you can get the outdrive to draw water from a bucket easily unless you pre-prime the pump. just too much suction head to deal with. remember, your pump is about crankshaft high. which would mean to get the pump submerged to prime, you would need the bucket to have water to the top of your outdrive. that would mean the bucket needs to be big enough to put your entire boat in it. you can get the bucket method to work on Mercruiser Alpha drives with the raw water pump in the bottom of the outdrive.

with my VP to run on muffs, I also tape the muffs to the outdrive to force water up the intake hose (or have someone hold the muffs tight against the drive). if I do not do that, the raw water pump will not prime. once the pump is primed, I can remove the tape.

Another thing that you will want to check when you are looking at your boat. between your raw water pump and the pickup in the lower unit is your power steering cooler. you may want to unbolt the cooler and back flush it. this cooler acts as a strainer and sometimes gets plugged with debris.

 

[Jhilton0816]

Found the answer, haha I looked at a water flow diagram on the service manual and sure enough I had been thinking the bottom port was the Intake when instead it is the outtake, hopefully I didn't affect much on the engine for running it with no water hahaha