What is the proper way to make sure my (fresh) water cooling system is working ? Can I just disconnect the seacock and run a hose to a bucket of water? Or does it need to be under pressure?
Thanks,
Joe
That is a good way to test. Putting a pressure source(garden hose from city water) will not test if the pump is doing it’s job since the pressure may be supplying the flow for a bad pump. I usually just put a bucket of water in the bilge and put the intake hose into it. That way the draw is about equivilant to what the pump normally sees. Hope this helps.
John
Thanks! I went ahead and tried that and got just a dribble of water out the exhaust. I will have to check the water pump and see if there is a problem.
Be very careful applying pressure to the water inlet. It is possible to force water through the pump to fill up the muffler and the cylinders. When you turn the key to start, you get water hammer doing very bad things to the cylinder, pistons and the injectors.
The safest way is to put the inlet hose in a bucket of water. If you match the height of the water in the bucket with the waterline of the boat, the pump will see the same water pressure as when the boat is in the water. Don’t crank or run the engine without water in the impeller as you can damage the it in very short time.
If you’re feeling really adventurous, a few gallons of straight pickling vinegar sucked up out of the bucket will push an amazing amount of built up crud out of your exhaust system, but pull out any good “pencil zincs” from the system first (replacing each with a “dead” one), as the acid will eat them up about as quickly as it does the lime deposits.
If all you’re getting is a dribble, figure out what the problem is first. Your heat exchanger may be plugged. If there are any missing vanes on your impeller, you will likely find them at the inlet to the heat exchanger (which will also seriously impair water flow).
Your mixing elbow is another source of water flow problems. It will frequently “coke up” enough to block the flow of the water into the exhaust hose. One way to help minimize this is to “rev up” the engine for a couple of minutes before pulling the kill switch to shut it down.
Do NOT run muriatic acid (in any concentration) through the system, however. I have done this in the past, but you sure wouldn’t want to do it in a marina or a boat yard…the only place that would be appropriate for this approach would be when anchored a good ways upwind of “nothing” with a good stiff breeze blowing the fumes away from your boat.
I’m a bit confused. Are you talking about your raw water pump or the fresh water (coolant) pump? It sounds like you’re taking about the raw water pump.
Also, have you checked the impeller on the raw water pump? That would be my first guess.
– Geoff
Thanks for your input guys! I took my tiny water pump off and -impellers look good. I tried to suck water from a 5 gal bucket placed next to engine, but could NOT get the engine to suck it up when hand cranking. Next I hooked the garden hose to the inlet hose for raw water filter/bowl; gave it just enough pressure to fill the bowl; turned her over and she started right up and water flowed out the exhaust pipe beautifully without any issues.
Thanks,
Joe