No water flow in raw water cooling system

[LIG-C27]

Apologies for an additional cooling system question.

I have a Atomic 4 ina Catalina 27 that is in kept in the Chesapeake. Coming into this season engine/cooling was working fine; however, this week I started the engine and had no water flow. I checked the water pump and found that the impeller was completely disconnected from the impeller shaft. I replaced the impeller shaft, impeller and the inner and outer gaskets that encase the impeller shaft. After re-starting the engine, I still have no water flow.

Additionally, I verified that there is not a blockage from the throughhole to the impeller pump.

Does anyone have any good ideas on what may be the cause and how I can proceed with troubleshooting the issue.

Thanks for the help.

[Baltimore Sailor]

Well, after making sure that the raw water through hull is open , I'd run the pump intake line into a bucket of water and prime the line. I've heard that sometimes the pumps don't self-prime well (mine did it to me once, but usually primes with no problem), so I'd do something to make sure that's not the problem.

[ndutton]

If you have any issues with Baltimore's suggested test, remove the impeller and measure its width and the pump cavity depth with a dial caliper. Differences greater than somewhere around 0.003" (impeller being smaller) and you'll have a devil of a time getting it to work.

[sastanley]

Welcome to the group.

When I rebuilt my water pump, I had trouble getting it to prime as well. I ended up filling the intake hose (funnel??) to get some water in the pump/impeller, then it was able to suck from a bucket..after that I reconnected the hose to the thru-hull & it was A-OK.

There is a whole other discussion about impeller problems, which Neil alluded to in his post. Hopefully that won't be your issue.

[rheaton]

Make sure you still have the shoe thing in the pump, and that it is in go od shape.

[hanleyclifford]

It might also be useful to check the output side. The spot that comes to mind is the discharge fitting at the back of the manifold.

[LIG-C27]

Thanks everyone for the advice. Looks like I have had a few issues that have compounded. My prime was good, but I had heavy silt or some other material within the water jacket that seems to have fouled up my thermostat, no allowing it to open up.

I took off the thermostat and saw water shooting through when I cranked the engine, so now I guess it is just an attempt to clean out the water jacket as well as a new thermostat.

Thanks again.

[skogie]

water cooling flow

I tried pouring white vinegar in the cooling manifold,left it overnight and fired up the engine next day. A bunch of black crud came out with a little water, and then a good steady pulse-flow of clear water. So far, so good.