Offshoreonly.com - Circulating pumps

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Quote:

Originally Posted by AllDodge (Post 4575239)

Probably a dumb question but how long did you let the motor run watching for water?

If it was a short time maybe it didn't have time to show up. Otherwise I don't see how water from a hose could make it past the water pump housing and a new impeller....... unless the hoses were connected reversed and it burned up the new impeller and then the water started being pushed thru

'96 7.4 MPI's w/B1's, Perko flush outs in my raw water pick up hose and water comes out the exhaust and drive on both engines when not running and hose on. New SS impeller housings w/impellers and none of the symptoms BUP described above.

Please don't tell me I have another project.......

Well, that's new and important information.

Does your Perko set up have one way valves in them ?

Water coming out without the motor running concerns me. While you might get a little leakage there shouldn't be that much.

The circulation pump may be an issue if water was flowing out and it was overheating, your not getting any water so don't see how the circulation pump would be in the equation right now. Just change to the stainless pump my self this season and it is working but I'm not so sure it is doing as well as the composite.

Another dumb question, you did happen to swap the hoses on the pump?

on Bravo impeller apps if the back side hoses are wrong for the impeller housing. the impeller will burn up around the 2 min mark and you can actually smell the rubber burning at the pump. that's on the water hose as well because it can not prime itself with water especially that far of run ie: drive water inlets all the way to the impeller pump

If the system is fully primed with water then the water will not move out of the pump. But if one changes impeller and black plastic housing the system is not primed after the new install unless one forces water self primes just before start up.

Quote:

Originally Posted by BUP (Post 4575266)

clear water hose method testing - you look for air bubbles and or less volumes of water passing thru the clear hose(s).. This form of testing pin points your problem area(s) and or cooling part(s) issues.

engine overheat is also signs of bad or going bad water circ pumps. But of course there is many other things for overheat / higher temps on top of.

ALSO --- This is how you test Water circ pumps with clear hoses in place of the OEM water hoses

Other forms of water circ pump testing is take of your belt off and spin the water circ pulley in in both directions - it should spin very freely and easy without noises especially bearing noises.

also other testing is to look very closely at the bottom weep hole - look for rust stains and or white water mineral stains out and down from the weep hole. Also when running the motor looks fro water leaks from the weep hole. Also temp swings are associated with a bad or water circ pump going out. Everything here is how one knows that water circ is bad or going bad. The water circ pump seems to be widely missed. IMO of it is over 10 years old I would change them out anyways or for new rebuilds. Totally would not reinstall a used WCP on a new or new rebuild engine.

If you need one I have them made in the USA for MOST MARINE apps including LS and LSA GM MARINE engines and even Ford marine apps.

I bought two of these when I did my motors this year. Very nice units and cheap insurance!

Quote:

Originally Posted by SB (Post 4575301)

Well, that's new and important information.

Does your Perko set up have one way valves in them ?

Yes haven't had a chance to remove them yet. Engines with 263 hrs., only 25 salt hours.

Did this issue start after adding the flush hookups?

Quote:

Originally Posted by Powerquest230 (Post 4575577)

Did this issue start after adding the flush hookups?

I've only run it with the flush kits. I assume the previous owner used muff's.

Keith

I guess a place to start is take hose off IN of raw pump and fire up hose hooked to perko unit. Then, once that side found ok, put hose back on raw pump and take off hose at IN of thermo housing. You should not get much out there with engine not spinning pump. Get lots when you fire up engine. Circ pumps go bad, but both at same time? Pretty much has to be something that was just done...