Sediment bowls
- Thread starter dehler25
- Start date
Burping...
Possibly. Water is sure to drain back and out once you remove the bowls to clean them, which may create an air bubble air lock. As both may be low enough to the waterline, hydraulic pressure and pump suction together may be enough to overcome it. It will depend on how much water drains out when you remove the bowl for cleaning.
The thing to do is to not fully tighen the bowl when you reinstall it, then open the thru-hull to flow water to the bowl to fill it. Tighten the bowl and fire each engine up to find out if it worked. That may be the only "burping" you need to do. Pulling the feed hose off at the pump and opening the thru hull may be the next step to get water to the pump if the above doesn't work.
Possibly. Water is sure to drain back and out once you remove the bowls to clean them, which may create an air bubble air lock. As both may be low enough to the waterline, hydraulic pressure and pump suction together may be enough to overcome it. It will depend on how much water drains out when you remove the bowl for cleaning.
The thing to do is to not fully tighen the bowl when you reinstall it, then open the thru-hull to flow water to the bowl to fill it. Tighten the bowl and fire each engine up to find out if it worked. That may be the only "burping" you need to do. Pulling the feed hose off at the pump and opening the thru hull may be the next step to get water to the pump if the above doesn't work.
Dan, the raw water pumps on both the engine and the generator should be self-priming. As long as sediment bowl cover is closed properly, not letting air in, the impeller should draw water and and normally not need burping.
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Check your exhaust discharge after starting the engine to see what's coming out. If it's submerged, check the mixing elbow temperature after starting.
As Claude has mentioned, the raw water pumps are self priming. They act as a positive displacement pump at lower RPM and a centrifugal pump at higher RPM as the vanes are swept back.
while they may be self priming, that assumes that no air is being sucked in...
so if there is a major leak at the gasket or bowl, they may never prime and suck air, and actually lose prime and suction...
After 45 years boating, I still check the exhaust for a healthy water flow. Each and every time.
so if there is a major leak at the gasket or bowl, they may never prime and suck air, and actually lose prime and suction...
After 45 years boating, I still check the exhaust for a healthy water flow. Each and every time.
I would say that "self priming" is a characteristic of the pump. "Leaks in the suction line" is a characteristic of the owner.
I can only speak for my boat, but Hunter did a great job of pump locations "below the water line" of the boat. This is good pumping design. You should check that the suction/input side of the pump, of your engine/genset sea water pumps, is "below" the boat's water line.
My sea water pumps are "flex vane" positive displacement pumps. Translation...
They pump air and water.
But...
They need water to lubricate/cool eventually.
So...
No need to "burp" them.
Holes in inlet line, to draw air, will be obvious with sea cock open and engine down. They will leak sea water!
Always...
Check the running exhaust lines for water "spitting" out, in a normal fashion, and for leaks inboard, after strainer cleaning. Engine temperature alarms/gauges will show problems too.
Jim...
My sea water pumps are "flex vane" positive displacement pumps. Translation...
They pump air and water.
But...
They need water to lubricate/cool eventually.
So...
No need to "burp" them.
Holes in inlet line, to draw air, will be obvious with sea cock open and engine down. They will leak sea water!
Always...
Check the running exhaust lines for water "spitting" out, in a normal fashion, and for leaks inboard, after strainer cleaning. Engine temperature alarms/gauges will show problems too.
Jim...
Claude and others..
The key words are "should be self-priming". I've had instances on my boat and working with others where that didn't happen. "Burping" confirms that there is water flow.
Last time my boat was put in the water I got no water flow out the exhaust at start-up, despite an open thru-hull and winterization anti-freeze still in the hoses. Loosening the raw water pump's hose produced no water flow.
Pulling the hose off the thru-hull barb and opening the valve resulted in no gusher. A rat-tail file cleaned out the mud-dauber plug in the intake, producing the expected geyser.
After reclamping and reopening the thru-hull, the raw water line at the pump was "burped", confirming waterflow through the strainer to the pump.
By going through all this, I avoided wiping out an impeller trying to get the raw water pump to "self-prime".
There was joy in Mudville that day!
PS: Remember, the bowls were being removed, cleaned, and reinstalled, creating a possible air-lock due to air induced from any raw water drain-back as I referred to initially.
The key words are "should be self-priming". I've had instances on my boat and working with others where that didn't happen. "Burping" confirms that there is water flow.
Last time my boat was put in the water I got no water flow out the exhaust at start-up, despite an open thru-hull and winterization anti-freeze still in the hoses. Loosening the raw water pump's hose produced no water flow.
Pulling the hose off the thru-hull barb and opening the valve resulted in no gusher. A rat-tail file cleaned out the mud-dauber plug in the intake, producing the expected geyser.
After reclamping and reopening the thru-hull, the raw water line at the pump was "burped", confirming waterflow through the strainer to the pump.
By going through all this, I avoided wiping out an impeller trying to get the raw water pump to "self-prime".
There was joy in Mudville that day!
PS: Remember, the bowls were being removed, cleaned, and reinstalled, creating a possible air-lock due to air induced from any raw water drain-back as I referred to initially.