Auxillary fuel pump

[Petercatterall]

After owning my boat for three years its a bit embarrasing to admit that I have only just sussed this pumps purpose in life....I think!! Boat has a side and a central fuel tank. Engine is fed from the central tank. The auxillary pump would seem to be for moving fuel from one tank to the other, I guess from the side to the centre.
Seems a usefull idea for several reasons. The pump does not work and I cant find a replacement (its just a stand alone electric thingy) any ideas ?? Am I right in my guess of the direction of flow? could I reverse the polarity to get the pump to work the other way?

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[ongolo]

Hi there,

I have installed an auxiliary fuel pump that makes bleeding of the diesel system very easy, also in case of emergency when filters are blocked, the engine can be kept running even if the filters get damaged and injector pump and nozzles, aslong as the extra hour might save the boat.

Also with clever arrangement you could:

a) move diesel from one to another tank and

b) prefilter a larger amount of suspect or dirty diesel.

I know two types of pumps also used on rally and racing cars, one has an elctric motor, but the polarity reversal does not reverse the flow or the pump will get damaged.

The other is of a magnetically actuated membrane with flow possible in one direction. Polarity sensitive I think (red goes to plus black to negative), these are the type that you hear vibrating as they pump, when pressure increases or flow gets less, pumping becomes slower and eventually stops.

This gives you an indication when your filters are filled and the injector pump is filled up.

Routinely, I switch my booster pump on for a moment before I start the engine. If it runs at all, then I assume there is a small leak somewhere and try to find it.

These manual feed pumps of the bosch type are a pain to bleed a system with prefilter and four filters.

regards ongolo



<hr width=100% size=1>1000 dream about it, 100 talk about it, 10 start and 1 completes it<P ID="edit"><FONT SIZE=-1>Edited by ongolo on 12/05/2004 21:01 (server time).</FONT></P>

 

[Petercatterall]

Thanks for the info I will get the details off the old pump in the hope that I can just do a straight swap. I can see that the system as set up (once the pump works) can be used to move the fuel from the saddle to the centre tank and as there is afilter on the line will do some prefiltering as well. Regarding the aid to bleeding at least the fuel in the center tank can be kept high (above the filters) as an aid to bleeding.
I just spent some time marking up the bleed points and checking spanner sizes and intend to practice bleeding as I dread having to do it in adverse conditions.

Regards

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