Raw water pump not pumping.

[Bob Christiansen]

I just replaced the impeller and put it back together and no water is coming out the exhaust. I’ve taken the cover off to make sure the impeller is spinning. I’ve tried pouring water down the hose after the pump. Not sure how to prime pump if I need to?

Topic

[Rob Schepis]

Good points about the new vs. old impeller priming and that restrictions that may be downstream having an effect…

[Tony Athens]

Looks like an original older QSB Sherwood pump.. It would not be the 1st time I have seen an old impeller prime as it has worn into the cam grooves, etc–A new impeller may not do that especially if you have extra back pressure because of a “never / unknown when or if ” serviced aftercooler..

Or as you suggested–something is wrong with it?– I guess it is possible the impeller came out of the mold with bad QC?  Why not just send the suspect impeller back for a peek/refund.. …  A factory Sherwood QSB pump / impeller uses 27000 as their impeller number.  Sold all over the internet/ebay

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Rob Schepis

[Richard Dodson]

new impellor

I coat my new impellors with either silicone grease or dawn detergent.   

[Rob Schepis]

They can get air locked and not self prime at times.  Lots of lube on a new impeller is key and really helps it prime itself.  Are you using lube on your impeller installs?

[Bob Christiansen]

After trying everything to get the new impeller to pump water, I took it out and put the old one back in and it worked fine. There must be something wrong with the new impeller. 

[Richard Dodson]

Pump

The raw water pump is a suction pump and does not need priming.  Assuming the sea cock is open and water is free flowing. Assuming you installed the correct impeller and a new key,  you have a new o ring on the removable plate the pump should pump. I’m assuming it worked fine before you changed the impeller.  

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