Raw water pump - electric

1

14May1995

Active Member
Joined
24 Jul 2005
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49
Location
Tavistock, Devon
www.xpressions.co.uk
Was talking to someone the other day who is not on the forum so said I'd post on their behalf...

He has a Sunbird (?) with twin V8 petrols and needs to replace his raw water pumps. Has seen electric versions at a fraction of the price and wondered if anyone knew anything about them or could advise!!! Personally didn't know such thing existed.

Anyone?

Steve
 
Not a good idea as they will just run at one speed unless he fits some type of controller thats fed with a signal to speed up the flow with higher engine rpm, id try keypart for new pumps that do the job well.
 
14May1995 said:
Was talking to someone the other day who is not on the forum so said I'd post on their behalf...

He has a Sunbird (?) with twin V8 petrols and needs to replace his raw water pumps. Has seen electric versions at a fraction of the price and wondered if anyone knew anything about them or could advise!!! Personally didn't know such thing existed.

Anyone?

Steve
Click to expand...

Sunbird were fitted with OMC cobra from memory. If so, the impeller raw water pump is in the leg. Why does he need to replace them?

If the engines are raw water cooled, which many of them were, the pump on the engine will also be pumping raw water, so maybe he is talking abut these. If so he should be able to pick these up as cheap as chips from the US.

I would stick with original setup, electric seems like a bad idea.


Edit: Hi Steve, how you doing :-)
 
Last edited:
I had a Sunbird with a single OMC 5.7. As far as I can recall the pump was in the leg. Never had a problem with mine. Good starter boat too. Last I heard it was on the East coast of Scotland.
 
neale said:
Sunbird were fitted with OMC cobra from memory. If so, the impeller raw water pump is in the leg. Why does he need to replace them?

If the engines are raw water cooled, which many of them were, the pump on the engine will also be pumping raw water, so maybe he is talking abut these. If so he should be able to pick these up as cheap as chips from the US.

I would stick with original setup, electric seems like a bad idea.


Edit: Hi Steve, how you doing :-)
Click to expand...

Hi Neale,

I'm good thanks. How's the 28? Are you just down the road from us still?

Suspect he's talking about the engines. He thought I knew more than I do!!!:-)

It was a very short conversation but I'll pass on all comments...suspect he doesn't use Internet so US supplies could be a challenge.

Thanks all though.

Steve
 
Electric pumps are very much a viable option on a boat, although they are a recent innovation on cars, trucks have had them for two or three years with considerable success.

Two types exist, and both are controllable, they are the fixed speed types and the variable speed types, and both are temperature controlled. Fixed speed types are simply switched on and off by a simple thermister switch similar to that on a cars electric fan, they do just that, switch on when temperature rises, and switch off when it drops. Variable speed types are an enhanced variant of the fixed speed type, they simply run for longer periods, but are able to vary their speed according to temperature, and also switch off when not required.
 
Assassin said:
Electric pumps are very much a viable option on a boat, although they are a recent innovation on cars, trucks have had them for two or three years with considerable success.

Two types exist, and both are controllable, they are the fixed speed types and the variable speed types, and both are temperature controlled. Fixed speed types are simply switched on and off by a simple thermister switch similar to that on a cars electric fan, they do just that, switch on when temperature rises, and switch off when it drops. Variable speed types are an enhanced variant of the fixed speed type, they simply run for longer periods, but are able to vary their speed according to temperature, and also switch off when not required.
Click to expand...

But is there any reason why you would want one on a boat?

Genuine question.

Belt driven pumps are pretty reliable, so what benefit would an electric pump bring? Maybe a very very small saving in fuel possibly, but on a V8 in a boat I doubt it would be measurable.

I'm thinking the KISS principle comes into play here and an electric motor running the cooling system on a boat in a damp salty environment isn't the best solution.
 
neale said:
But is there any reason why you would want one on a boat?

Genuine question.

Belt driven pumps are pretty reliable, so what benefit would an electric pump bring? Maybe a very very small saving in fuel possibly, but on a V8 in a boat I doubt it would be measurable.

I'm thinking the KISS principle comes into play here and an electric motor running the cooling system on a boat in a damp salty environment isn't the best solution.
Click to expand...

+1
 
Like most new equipment, people are often reticent to fit such items, and like most things they have pro's and con's.

They only work when required, thus reducing engine warm up times and fuel consumption during such times, in operation they do the same, only work when required and save reasonable quantities of fuel. If we compare a mechanical water pump we see it has two bearings or one large bearing, an impellor, a seal, a drive shaft and a pulley, all things to leak or go wrong. By comparison an electric pump has only one moving part and is a fully sealed unit so no potential for leaks through seals, slipping or breaking drive belts, or pulleys coming loose.
Electric pumps also last much longer than a mechanical pump as they only operate when required, not constantly as a mechanical pump does, and when the engine is switched off they can be wired to continually run to cool down a hot, shut down engine.

Downsides are their cost and availability, not being popular just yet means higher purchase prices and more limited availability for a number of applications. Installations of electric pumps must be done correctly, this means the correct cabling and fuse/breaker size, and the correct by-pass wiring arrangement. By pass arrangements are switches at the helm/s to run the pump continually if the thermister switch fails.

There are no hard and fast rules, but each individual must make their own choice on fitment or not based on their circumstances.
 
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