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Carby help
joesbuell - August 8th, 2014 at 02:44 PM

My Empi 34epc carbs flood after engine is shut off. There the same carbs I had with my old motor only I changed the jets back for the bigger motor. Rerouted fuel lines as per my mates car. Getting frustrated any ideas much appreciated thanks.


Bizarre - August 8th, 2014 at 06:16 PM

needle and seat stuck??


joesbuell - August 8th, 2014 at 06:55 PM

Checked and rechecked


SunshineKarmann - August 11th, 2014 at 01:15 PM

Mechanical or electric fuel pump?


joesbuell - August 11th, 2014 at 03:28 PM

Mechanical


psimitar - August 11th, 2014 at 08:35 PM

Check the fuel line pressure. More than 3.5psi and you'll have flooding issues. Residual line pressure could be causing the problem if the line pressure is high whilst engine running.


68AutoBug - August 11th, 2014 at 11:24 PM

Hi Jodie

The length of the pump shaft can be incorrect, resulting with fuel pressures of around 10psi [so, I've read] or even higher..

so, I agree that its residual pressure after the engine is turned off..

You can shim the base of the pump up to the correct position to lower the fuel pressure..

Lee


joesbuell - August 14th, 2014 at 11:26 AM

Checked all those things Lee, still no joy. I ran some ethanol blend fuel in it and seams to have loosened the fine rust inmy tank I have 2 fuel ffilters and shit still getting in carbs. I have a new fuel tank I bought at Valla but haveto put a new filler neck on it as it was bought as damaged stock. Anyway thinking of putting some twin 40 webers/empi or delortos on it.

Ill try and check fuel pressure over the weekend.


matberry - August 14th, 2014 at 11:39 AM

No carburettored car should ever have Ethonol blended fuel in it

Changing your carbs would be a good move IMO


joesbuell - August 16th, 2014 at 11:10 AM

Thanks Mat


psimitar - August 16th, 2014 at 05:08 PM

Quote:
Originally posted by matberry
No carburettored car should ever have Ethonol blended fuel in it

Changing your carbs would be a good move IMO


Why so? Eats the aluminium or gumming issue?


68AutoBug - August 16th, 2014 at 11:57 PM

My 68 Beetle doesn't go well on Ethanol fuel..
I lose a lot of power...
and it goes great once the ethanol fuel is removed and replaced with non ethanol fuel...
so I make sure I don't buy any fuel with Ethanol..
Most old servos still have NON Ethanol 91..
or 95 or 98

Most bowsers have stickers on them saying NOT to Use E10 with Ethanol in Motor Cycles or Marine engines..
should also include Air Cooled VWs..

LEE


modnrod - August 17th, 2014 at 06:39 AM

Quote:
Originally posted by psimitar
Quote:
Originally posted by matberry
No carburettored car should ever have Ethonol blended fuel in it

Changing your carbs would be a good move IMO


Why so? Eats the aluminium or gumming issue?


Softens the rubber O-rings, seals, etc, so they slowly perish putting a rubber mud through the carbs. Slowly attacks the aluminium castings (some are worse than others here) to create a fine silty alloy mush through the fuel system which clogs everything.
And in this case, possibly maybe perhaps, can get to the Viton tip on the fuel inlet needle, so it goes soft and won't seal against the seat properly making a slow drip into the motor.


matberry - August 17th, 2014 at 08:59 AM

Yes to all above, but most of all, the mixture MUST change. With carbs, fuel is metered by the jets, these only change the amount of fuel delivered by changing jets. A later EFI engine monitors the exhaust gas and changes the mixtures to compensate any differential in fuel by changing the timing of the injectors, ie. if it senses a lean condition, the computer puts in more fuel, carbs don't do this. With alcohol fuels, roughly 3 x more alcohol fuel is required to creat the proper fuel mixture. So even a blended fuel requires an increase in fuel delivery to create the proper combustion. A carby engine on alcohol without increased jetting WILL run lean, no question, and a blended fuel actually never the same amount of % of alcohol as it evaporates out of the fuel so it is imposible to tune for accurately, one day it may be right, the next not. Only EFI can monitor exhaust and regulate fuel delivery.


fish26 - August 17th, 2014 at 11:07 AM

Does anyone know how to set up dual Empi EPC 34, i built a 1776cc for a mates DC, runs fine but they can't get it to Idle just dies below 1200rpm otherwise very responsive
C25 cam 7.4 C/R
stock valve 040 hemi heads
chromoly pushrods 002"
009 8* BTDC 28*total
Holley pump and reg 2psi
I will be getting the engine back on Tuesday to try and sort it out on the bench

I doubt the carbys are correct out of the box so any help is appreciated.


modnrod - August 17th, 2014 at 01:20 PM

Throttle plate setting at idle correct for transfer slots?
Solenoids energised OK? (if they have them?)
Holley regs are bloody horrible things at less than 4 or 5psi, I'd double-check.
Just a few.


psimitar - August 17th, 2014 at 11:12 PM

Matt n Modnrod, ta muchly for the explain. Always nice to learn something new :)


joesbuell - August 31st, 2014 at 11:53 AM

I replaced my fuel tank with brand new wolfsburg west one. Fitted a carter rotary electric fuel pump running just over 2 psi. My question now is if anyone is running 34ict/epc carbs what jets and emulsion tubes? My motor is 1641cc 1.25:1 rockers.

Stock mains 130
emulsion F6
idle jet 55
pump 40

cheers


psimitar - August 31st, 2014 at 10:51 PM

Quote:
Originally posted by joesbuell
I replaced my fuel tank with brand new wolfsburg west one. Fitted a carter rotary electric fuel pump running just over 2 psi. My question now is if anyone is running 34ict/epc carbs what jets and emulsion tubes? My motor is 1641cc 1.25:1 rockers.

Stock mains 130
emulsion F6
idle jet 55
pump 40

cheers


135 for mains and I think, been 14years since I did mine, that F11 tube gets rid of the flat spot just off idle that occurs with a 009 dizzy.