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electric fuel pump


kelvinnoel

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hi guy,s ,help needed ,do i need to have a pressure switch fitted to the fuel pump ,it runs constantly even on tickover,also would this cause the plugs to soot up ,they come out black even after a good blast ,I,ve adjusted the mixture screw but it seems to make little difference ,there is a ramair air filter fitted and the choke is fully open ,the timing is spot on ,new distributer ,plugs and leads I,m at a loss.and in case you haven,t noticed it,s almost summer ,I need to get back on the road but be a little quicker this year

 

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The pump will run all of the time. It may be that it is over fuelling the carb or carb's.  Fit a fuel pressure regulator, one with a filter element is not a bad idea. My twin 45s are set to receive only about 3psi if my memory serves me correctly. Get the right pressure at the carb then start fiddling with mixtures or better still get it on the rolling road.

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As above. The fueling of a DGV is affected by fuel level in the float chamber. Too high and the engine runs rich.

So set the float level correctly and make sure the needle valve is not leaking. Then feed it at the correct fuel pressure. To high a pressure can overcome a correctly set needle valve and float and overfill the chamber. Ideally use a low pressure/high volume rotary pump with output in 2.5 to 4psi max, not more. Pulsing electric pumps like the Facet square block type can upset webers and I hate them with a vengeance anyway! Using a higher pressure pump and then having to fit a 'regulator/flow restrictor' doesn't make sense.

Once you have the engine running with correct stable float level the carburettor adjustment screws start working.

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If you do decide to fit a pressure regulator fit it as near to the carb as possible. Just because a pump is rated to give 6psi at the tank doesn't mean it will give that at the carb. Frictional loss. Surprising what difference that can make. I guess it's up to you what which path you take, as said before its pointless having a high pressure pump and then putting a regulator on it but a regulator will control what you are getting at the carb regardless. I plumbed in a temporary pressure gauge at the carbs to get my pressure right and have never had any more problems with leaks or flooding since. Looks like there isn't much difference between the price of the regulator and a pump either! 

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the weber is new fitted by the last owner ,so i assume it is in good condition, the car has only done 2000mls since ,but work means i only get weekends to work on it .I will check today on the pump and then decide my next move ,and thanks a million guys for the advice

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Main problem with the mechanical pump is that it's not too clever for starting the car if there's not much fuel in the carb. I used to find that after the car was turned off and left for a long period of time, the underbonnet heat evaporated the fuel in the carb and it needed to be cranked for an age to full the bowl before it would fire.

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The standard mechanical pump was Not fitted when I got the car ,the electric one is an eBay cheapy,it works fine but there is no adjustment so I have ordered a pressure regulator ,more to come,as soon as I fit it ,on a similar vein in my younger years I raced banger cars and always used electric fuel pump,s and they were fitted with a pressure switch that cut the power once pressure was achieved restarting again as required ,where are they now???????

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