Thread: Why Mr Lucas?

Hi Lionel,

When I put an electric fuel pump on my Series 3 I put a cutout switch which I believe is the type you mentioned above as a tach based one. They are cheap and easy insurance, if the engine is not running then it cuts the pump. I would not be as worried about the power source (provided the wiring is adequate for the current carried and is fused) as I would be about cutting the petrol in the event of an accident. If the vehicle is on it's side or upside down then petrol comes out of a carbie through the vents no matter what you do so if you can limit that to just the contents of the float bowl then it is a good thing.

You can get a much better result from fuel injecting though as no petrol flows that you don't want, no matter what the angle, and the pump cuts out automatically when the engine stops .

Cheers,

Tim.

Hi Folks,
You chaps seem to know what you are talking about when it comes to electric fuel pumps.
My Series III has an auxiliary tank under the passenger seat plumbed through a change-over tap located immediately behind the center seat.
All was well until a recent trip where I emptied the main tank and was running home on the last of the auxiliary tank (still had about 10 litres in it). The engine began to hesitate and then intermittently die as I was ascending the last hill on the freeway before the exit to the shed where the Series is stored when not in use. It felt like fuel starvation. I was able to encourage the beastie over the crest by lifting off and working back through the gears. Once the load came off (flat ground) we motored along happily to the shed.
The auxiliary tank sits over the top of the exhaust pipe with only a shield protecting it from the heat. So the fuel in that tank does get a bit warmer than in the main tank. Plus, it's a fairly long run from the auxiliary tank to the carby. I wondered if the low level of the tank put too much low pressure on the fuel line causing vapourisation, or maybe the mechanical fuel pump couldn't lift that far.
So maybe I should put a fuel pump near the auxiliary tank to keep the pressure up in the system when the auxiliary tank is being used.
The machine is running fine now that the tanks have been refilled.
How would you set up such a fuel pump? I figured a switch on the dash so that I could turn it on only when needed.
Any suggestions?
Cheers

Coop