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Fuel Pressure


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#1 Agus1601

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Posted 13 November 2017 - 05:57 PM

Hi Guys! I am looking forward to re install my hif44 on my nearly standard 1310cc classic mini.

 

What do you think? I am curently using a very old hs4 carb but think problem may be the electric fuel pump used, which should I use? Or do you recommend me using a regulator?

 

Also looking forward to upgrade the wheels on it, they have to be some 13 inch good wheels

 

Thanks

Agustin



#2 Wim Fournier

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Posted 13 November 2017 - 06:03 PM

Yes. When using an ordinairy carb and have an elctric fuel pump you must use a pressure regulator. Electric pumps are far to powerfull for the float to withstand the pressure that the pump exerts on the needle. When the float can't close the the needle in the seat, fuel will be coming and coming and the carb will overflow constantly. Not in the farthest way you can control the mixture.



#3 nicklouse

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Posted 13 November 2017 - 06:15 PM

it depends on the Electric pump there are many that do not need a regulator but if the pressure is greater than about 3PSI then you will need one.



#4 carbon

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Posted 13 November 2017 - 09:01 PM

+1. Most Minis before early 70's were fitted with SU electric fuel pumps. As Nick says these only put out about 3 to 4 psi and don't need a regulator.

 

Even with a high pressure fuel pump the float should be OK as the chamber is vented to atmosphere. However if the carb is sealed for blow-through supercharged or turbocharged then indeed the float will need to withstand increased pressure.



#5 Agus1601

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Posted 14 November 2017 - 10:59 PM

Thanks for your replies guys! I am really trying to sort things out but will star by adding a fuel pressure regulator. Which one do you recommend me to use?



#6 nicklouse

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Posted 14 November 2017 - 11:16 PM

first get a means of testing what your fuel pressure is. then add a regulator if needed. of fix the carb if it is not holding the pressure.

 

it may just need the needle and float looking at and a regulator would do nothing.



#7 Agus1601

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Posted 14 November 2017 - 11:37 PM

ok so If I desassemble carb what should I look for? I have changed needle and also upgraded the spring. Changed the jet, it has a fixed jet on it, and needle used is the one from stg 1 kit

 

Thanks a lot

Agustin



#8 nicklouse

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Posted 14 November 2017 - 11:58 PM

first you need to know what the actual pressure is. 

 

and then if you have issues then look to fix.

 

you dont actually say you are having any issues.



#9 Agus1601

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Posted 15 November 2017 - 12:29 AM

My car does run ok but want it to run better, always want to fill it is perfect. Also my neighbours sont like the smell it leaves in the building :(



#10 Ethel

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Posted 15 November 2017 - 12:38 AM

Facet pumps are available with the pressure set for SU's. Considering your location, they could be harder to find off the shelf, but obtainable from a Facet stockist.



#11 Agus1601

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Posted 15 November 2017 - 12:43 AM

Facet pumps are available with the pressure set for SU's. Considering your location, they could be harder to find off the shelf, but obtainable from a Facet stockist.

No one supplies facet fuel pumps down here... Thats why I am thinking of testing the pressure my fuel is sending right away so as to take control of it first.



#12 cal844

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Posted 15 November 2017 - 04:09 PM

Sounds like it's running rich, it will when on choke, what you want to do is go and get a co meter set mix to 3% on meter, this gives you a little room for manoeuvre at test time. You may also find that the AAU is too rich(as it is in my estate, by a mile!)

Why not import a pump since you now know the pressure you need

Edited by cal844, 15 November 2017 - 04:10 PM.


#13 carbon

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Posted 15 November 2017 - 07:35 PM

Agustin,

 

Do you have an in-line fuel filter fitted?

 

With old steel tanks there can be a steady supply of rust particles coming through with the fuel. A small bit of rust on the float needle is all it takes to cause carb flooding, regardless of the fuel pressure.



#14 Agus1601

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Posted 15 November 2017 - 11:04 PM

Sounds like it's running rich, it will when on choke, what you want to do is go and get a co meter set mix to 3% on meter, this gives you a little room for manoeuvre at test time. You may also find that the AAU is too rich(as it is in my estate, by a mile!)

Why not import a pump since you now know the pressure you need

Sounds like it is running to rich, atm the car is being restored from the exterior to fit new 6*13 inch wheels so... By the time I get it home I will disasemble the carb and try to work it out the better way.

 

Maybe it is not well carbed and I really think know that something is happening with the fuel pump because it keeps constantly charging, I am hearing the sound much often than before



#15 gazza82

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Posted 18 November 2017 - 04:06 PM

The HIF44 is probably a better carb for the 1275 and being newer (assumed) is probably also less worn. You can get kits from Burlen in UK to recondition it: gaskets, jets, needles, etc.




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