Raw water pump

[Randomwake]

Thinking about switching the raw water pump on my 120 cord Lehman from mechanical to electrical 12v pump. Thoughts?

 

[Simi 60]

On what?

Main engine no
Genset yes, but 110v better

 

[Randomwake]

I edited the post to clarify. It’s on the engine for 120HP Lehman.

 

[Simi 60]

As the engine changes rpm it needs more water
How does that work with electric?

Saying that I have a 240v onga Balboa pump as an emergency pump but that'll only come into play if my spare same same and ready to go belt driven pump has failed.
The onga is pretty close to matching engine water flow at full noise but we never run close to full noise.

 

[Comodave]

I wouldn’t do it.

 

[Nick F]

Personally, I would not do it.
However, how about listing what you think would be the advantages, and the disadvantages, and let´s have a more constructive assessment of this proposal.

Regards,
Nick

 

[Juliet 15]

Just thinking - I never had a problem with my cars water pump. How come boat pumps are so failure prone. Just sayin'...

 

[Comodave]

Just thinking - I never had a problem with my cars water pump. How come boat pumps are so failure prone. Just sayin'...

Probably because boats are water cooled and cars are air cooled and they don’t have raw water pumps.

 

[syjos]

Eliminating the seal and the bearing with a mag drive pump would be the only advantage. But I don't know what the biggest mag drive pumps available are. Plus I'm not sure if pumps other than centrifugel pumps are available as a mag drive.

Standard engine mounted RW pumps are usually self priming, move huge amounts of water, easy to maintain and last a long time.

Rebuilding them is easy and does not require specialized tools.

Down side is the periodic impeller change.

 

[2savage]

If it ain't broke, don't fix it. If you have Benjamins burning a hole in your pocket I'll send you a PM with my wire transfer info.

 

[BruceK]

If yours is a worry,ADC does an upgraded rw pump for $500. The drive doesn`t break unexpectedly and you`ll have a brand new pump.Better than trying to go electric imo. And you still need a belt to drive the alternator.

 

[jleonard]

The newer Johnson pumps that ADC sells for a replacement are pretty reliable and give excellent longevity. Mine (Johnson) was 15 years old and still running fine. Impellers are cheap and easy to replace n those.
As engine speed changes you need more water and the on-engine pump does that.
You won't get that with an electric pump. With an electric pump you'll have the possibility of corrosion on connections and another potential problem/breakdown.

I would stay mechanical and not do electric pump for this situation.

 

[C lectric]

Just thinking - I never had a problem with my cars water pump. How come boat pumps are so failure prone. Just sayin'...

Your car only had only ONE pump that that was immersed in coolant which is also a lubricant and , unless something is seriously wrong with the car engine, has almost no dirt or debris running through it.

Think about your raw water pump moving a corrosive fluid that is full of junk that can be harmfull to your pump and that is NOT a lubricant except in the most basic way.


THe raw water pumps, impeller type, as they are, are also self priming, which a car/automotive pump is not. This would also be the case with an electric centrifugal pump, no auto priming meaning also that if conditions are rough and the intake is exposed to air over a big wave the electric pump could lose its prime and stop pumping water.

I also suspect that each time the engine is started, if the water level is not above the actual pump, it will need to be manually primed.

 

[omoore]

The drive shaft bearing on the raw water pump on my 120 Lehman just went. The wobble broke the couple where the shaft joins the pump. Last 51 years so I can't really complain. LOL. The Am Diesel replacement is a much better pump. If I get around to it I will replace the pump in the other engine.

 

[kapnd]

Just thinking - I never had a problem with my cars water pump. How come boat pumps are so failure prone. Just sayin'...

This thread is concerning the raw water pump, an entirely different breed of cat, but don’t ever think that anything mechanical is bulletproof!
This happened to my motor far from land or help, wound up pumping salt water through the coolant loop to get home.
There was a (anti cavitation?) ring welded behind the vanes that came unglued, jammed the pump, dumped the coolant, and fried the serpentine belt. Funny that the new replacement pump doesn’t have that ring on it!

In answer to the OPs inquiry, I have two salt water pumps in service in the ER that could easily be modified to feed raw water to the engine, so no, I wouldn’t.
For a real emergency, a manual pump, or a pump driven off the engine would be better than relying on electric.

 

[Cartouche]

Thinking about switching the raw water pump on my 120 cord Lehman from mechanical to electrical 12v pump. Thoughts?

I would not what happens when you shut the engine down and forget to turn off the water pump.??

 

[rwidman]

Why?

 

[Cartouche]

Why?

it will fill the muffler and then regress back into the engine.