Raw water pump

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Joined
May 2, 2016
Messages
20
Location
USA
Vessel Name
Remedy
Vessel Make
Senator Sport/Fisher 31
I have read alot about raw pumps and Impellers etc on the forum. Has anyone tried an electric pump replacement. What volumn does a 4 cyl. Lehman require. Is this just a bad idea. I was thinging of getting one for a backup. It would be a quick repair. Wondering? Archie Bricker
 
Don't know if it's been done on the main engine, but there were a couple of people who switched there genset to electric raw water. While it should work, bare in mind, there is more to picking a pump than matching gallons per minute. Head pressure especially if you are using a lift muffler, needs to be considered.

Ted
 
Not sure why you would not want to use the standard pump and carry a spare impeller. Impeller replacement is simple usually. Much quicker than swapping out a different pump. Also, If you were to use an electric pump, make sure that it cannot run if the engine is not running. Otherwise you will quickly fill the exhaust system with water and back foo the engine. I suppose it could be done, but why???
 
Not sure why you would not want to use the standard pump and carry a spare impeller. Impeller replacement is simple usually. Much quicker than swapping out a different pump. Also, If you were to use an electric pump, make sure that it cannot run if the engine is not running. Otherwise you will quickly fill the exhaust system with water and back foo the engine. I suppose it could be done, but why???

Sometimes it's not the impeller. Good to have a spare pump.

20160727_084037.jpg

Yes, I had a spare pump on Tuesday.

Ted
 
Is that a lobe that broke off the end of the shaft? If so any idea why, did the pump jam up somehow?
 
Pump had 110 hours on it when the blade snapped off. Pump isn't bound up. Took the impeller out. Shaft with bearings and seals turns freely. I guessing those shafts are hardened. Maybe this one was to hard and became brittle.

Ted
 
Not on a main engine. The pumps is designed and installed to vary flow with engine speed. Maybe someone got away with one on a generator with its constant RPM, but that's news to me.
 
Your searches might show there is an updated raw water pump available from American Diesel Corp (Lehman successors) for the L120, it`s a Lehman marinizing part and may also fit the L80.
 
It's not uncommon on gensets.

But there can be priming issues.

An electric pump can make a good backup pump for a main engine.

In a pinch you can use a bilge pump or a air con raw water pump, etc.
 
There was an Onan generator model many years ago that when the seal on the water pump went bad, it let water into the engine. Many owners replaced it with electric pumps. It worked fine but as George pointed out generators run at a constant rpm.
 
I don't run the genset a lot, but the electric pump I installed for my Onan 7.5KW seems to work great so far. And since it's powered from the generator side, no worries about the pump running if the motor isn't. I do check for good flow each time I start it, in case it loses prime. Only happened once, after a long period of traveling without using it.
 
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