Cummins Guys Raw water pump question

[scenarioL113]

I am down to the final of final things to complete this repower project.

I was testing the raw water system today, full 5 gallon bucket with garden hose supplying it. My port engine would not self prime, even after sticking garden hose in it ( water was just passing through it). I took the impeller out and all looks to be good, its a brand new impeller and it is spinning via the front gear drive.

The gasket didnt look too good so I replaced it and put all back together and tightened the bolts good and snug. It worked fine for 30 seconds and then lost prime and I revved engine up a bit and she started pumping fine and was good for about 5 minutes and I left well enough alone.


Anybody ever experience anything like that before?


Frank

[In Memory Walter K]

I have had some priming problems at the beginning of the season in recent years. I won't leave the slip the first time without putting my hand on each pump while warming up. If the pump body isn't cold real quick, I know I have to check for the reason why. I have found bad impellers, bad cam, worn side plate, untightened hose clamps, cracked intake hose and most recently a bad cork gasket on the top of my sea water intake strainer.

[Harry Babb]

It sounds to me like there is surely a problem.

How far from the pump is the 5 gallon bucket?

The pump should pick up prime pretty quick if the bucket is anywhere near the pump.....and once it picks up prime it should empty the bucket in about 30 seconds or so.....even with a garden hose supplying it.

I don't know about the 4BT's but the 6's I believe pump 15 or 20 gallons a minute.

Do you know if the plates on each side of the impeller are in good shape?

Keep us posted

H

[scenarioL113]

The plate on the inside had some grooves in it and I reversed it, which made a big difference.

I dont know of a second plate tho, where would it be?

[In Memory of Vicroy]

Because the Sherwood pump is the prime weak link in an otherwise pretty much bulletproof engine, just go ahead and order the aftermarket impeller, wear plate, and cam from Tony Athens and rebuild both pumps now and get it over with. His kit will come with new gaskets and o rings.

You probably got an air lock or dry impeller leaking air. I use Dawn to lube the new impellers as they will burn up real quick run dry...like Walt says, check the temp of the impeller housing either by hand, or better with an IR temp gun to make sure they are cool after start up.

But rebuild the damn pumps now, the stock Sherwood impellers, cams, and wear plates are trash and will cause you nothing but grief.

UV

[scenarioL113]

Ok

I replaced the CAM and the WearPlate, has a new impeller already. Seems good to go!



Thanks



Frank