Adam, the diaphragm has a hole in it...
[edit] woops I thought you meant the bleed hole in the pump, my bad.
Please disregard, I was low on caffeine...
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| Electric fuel pump SU overflow https://www.ausmini.com/forums/viewtopic.php?f=2&t=79614 |
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| Author: | adamstuart [ Fri Dec 21, 2012 4:24 am ] |
| Post subject: | Electric fuel pump SU overflow |
Heres a question for the gurus. I hooked an electric fuel pump up to my morris 1100 as the mechanical one is not playing nice. When I wire it up directly to the battery (temporarily) it pumps fuel fine, but once it fills the float bowl it spurts out below the inlet. There is a hole there which I assume is a relief hole. It's the stock 1-1/4 carby and a normal facet electric pump I've got the pump in the engine bay currently. I've tried having the pump on the same level and also lower than the float bowl with the same result. Does anyone have any ideas? Will it stop once I wire it into accessories? (I don't think so) |
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| Author: | Irish Yobbo [ Fri Dec 21, 2012 7:05 am ] |
| Post subject: | |
That other pipe that comes out from the bowl is an emissions thing, I think it goes to the charcoal canister. Wherever it goes, there shouldn't be any fuel coming out. Your problem will be the float valve. Once it fills, the valve should shut off the floe well before it reaches the top of the float bowl. Since it's overflowing it looks like that's the problem. What pressure are you running the fuel pump at? |
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| Author: | drmini in aust [ Fri Dec 21, 2012 7:26 am ] |
| Post subject: | |
Adam, the diaphragm has a hole in it...
[edit] woops I thought you meant the bleed hole in the pump, my bad.
Please disregard, I was low on caffeine...
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| Author: | adamstuart [ Fri Dec 21, 2012 10:07 am ] |
| Post subject: | |
Irish Yobbo wrote: That other pipe that comes out from the bowl is an emissions thing, I think it goes to the charcoal canister. Wherever it goes, there shouldn't be any fuel coming out.
Your problem will be the float valve. Once it fills, the valve should shut off the floe well before it reaches the top of the float bowl. Since it's overflowing it looks like that's the problem. What pressure are you running the fuel pump at? There is no other pipe coming out of the float bowl. It's a small pin hole directly underneath the inlet. You can't see it if there is a fuel hose on there. I suspected the float, but didn't have time to check before work. I'll have to grab another from the parts bin and see how I go. Not sure about what PSI, the pump came straight off my moke and went straight onto the morris. Worked fine on both 1-1/4 and 1-3/4 setups. Thanks for your help. And Doc, do you think it's something other than the float? Not sure why it would suddenly have a hole in it, everything worked fine before it came off the car. |
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| Author: | Morris 1100 [ Fri Dec 21, 2012 10:20 am ] |
| Post subject: | |
Give the lid of the float chamber a whack with a plastic handled screwdriver to dislodge the bit of grit that is holding the needle valve open. Then order a Goss rebuild kit for your mechanical fuel pump. Part number 631VC. |
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| Author: | Convertible Mini [ Fri Dec 21, 2012 5:30 pm ] |
| Post subject: | Electric Fuel pump. |
Make sure it is not the pump that you have. There are different pressure pumps. It might be the one you have supplied too much pressure. You need one with no more that 2.5 to 4 PSI. |
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| Author: | kirby [ Fri Dec 21, 2012 9:31 pm ] |
| Post subject: | |
Or a pressure regulator. Which is a must on yumcha pumps but I trust facet to supply what it says on the box. Id be looking at the float first too. |
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| Author: | IndigoBlueCooperS [ Sun Dec 23, 2012 7:31 am ] |
| Post subject: | |
There are different Facet cube fuel pumps - high and low pressure. Like Convertable Mini said, you should use the low pressure one, not the more common high pressure one which is typically red. High pressure one may work OK, but it depends on how much pressure loss you have in your fuel line and how good the needle and seat is. |
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| Author: | miniron [ Sun Dec 23, 2012 9:40 am ] |
| Post subject: | |
Apart from making sure the fuel pump pressure isn't above approx 2.5psi check the float needle and seat. They come with 3 different size holes in them. From Midel catalogue circa 1993 AUD9095 small hole - use in BMC A & B series engines AUD9096 large hole - use in large 6 cylinder engines such as BMC C series, Healeys, Jags etc T3 Special very large hole 1/8" dia - turbo, S/C applications etc Make sure you use the small hole type. If you have the large hole type you are just making the flooding problem worse. SUs do not like fuel pressures above approx 2.5psi. The float is small and doesn't have much bouyancy and the float arm leverage ratio is also small compared to more conventional carbs so the amount of force applied to the float needle is also small and can't overcome high fuel pressures. New floats seem to the all plastic type without any obvious method to adjust the float level. You can't bend the float arm as on the original type floats. To adjust the fuel level SU provide 0.010" thick aluminium washers which go on the threaded end of the needle seat where it screws into the lid. Part No AYB0377. Hope this helps RonR |
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