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Carb Flooding.. You gotta see this


Dudeland

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Mike

 

That is the one you use when you have a turbo on the car. If you are getting an electric fuel pump, get a 2-4 lb one and you don't need a pressure regulator.    Take the valve out, it was only used with the emission s%$t  Plug the vacuum pickup with a plastic cap.  Have the fuel line go directly from the pump to the carb. Leave the original pump in place..

 

Rick

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18 minutes ago, stephers said:

Take the valve out, it was only used with the emission s%$t  

 

How does that valve affect emissions?

 

     DISCLAIMER 

I now disagree with some of the timing advice I have given in the past.  I misinterpreted the distributor curves in the Blue Book. 

I've switched from using ported-vacuum to manifold, with better results. 

I apologize for spreading misinformation.  

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53 minutes ago, '76mintgrun'02 said:

 

How does that valve affect emissions?

 

 

The fuel return valve was designed for use with the Solex carb...which has a "timed" vacuum port that would only allow vacuum at idle speed. It also has a ported vacuum which only sucks "off idle".  And, it uses manifold vacuum for the distributor advance, activated by temperature switches, a relay and electro-valve (black). 

I don't know if the return valve is an emission component. The stock mechanical fuel pump puts out 3.5 to 4.0 psi, which is reduced to about 2.5 psi when the fuel return valve is actuated.

How would this influence emissions?

PS: It would be ideal to have the fuel return valve open at all times, thus providing a constant 2.5 psi to the Weber carb.... as long as the flow rate was sufficient. 

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Thanks again John.

It does not seem like emissions equipment to me, which is why I asked.

I do think people see it as such and thus throw it away; as was probably the case with my car.

Seems like a useful component to me.

     DISCLAIMER 

I now disagree with some of the timing advice I have given in the past.  I misinterpreted the distributor curves in the Blue Book. 

I've switched from using ported-vacuum to manifold, with better results. 

I apologize for spreading misinformation.  

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4 hours ago, Simeon said:

 

Vacuum goes when the engine stops as well, so this would have to assume that excess pressure is bled off immediately prior to shut off, else the valve is closed again.

 

So three things happen at shut-down:  Fuel pump stops pumping, vacuum stops sucking, and fuel return valve closes.

Wonder what happens to the fuel pressure between the return valve and the carb?   High, medium or low?

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1- make sure fuel return line is not blocked

2- confirm check valve (if still there, connected to fuel return line) operating properly

3- by-pass fuel return valve all together. connect piece of fuel hose from fuel pump to carb with a tee in the middle and connect it to fuel return line.

What you have done to the car lately? Is this problem you been having every since installed new carb?Let us know what you find.

76 2002 Sienabraun

2015 BMW F10

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I haven't made any changes to the car for about 2-3 months.  I set up a 123 with an MSD 6A and have been monitoring the situation. I did melt the rotor (due to the resistor being in it) and replaced it with a solid no resistor rotor.   I am taking it apart tomorrow and I will let you know what I find. 

 

 

"Goosed" 1975 BMW 2002

 

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drifting off topic, but you should get one of these and then tell us how cool it is...

https://www.summitracing.com/parts/msd-8680?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-msd-ignition&gclid=Cj0KCQjwlMXMBRC1ARIsAKKGuwjMoxYXB0U8LmikuwOIgHyyaOowxhLxqTGV4N_lShbeBAUhAgHvwpMaApUeEALw_wcB 

 

MSD Ignition 8680 - MSD Adjustable Timing Controls

 

adjustable timing on the fly!

that might help tell you where to set the curve in your 123 gizmo.

     DISCLAIMER 

I now disagree with some of the timing advice I have given in the past.  I misinterpreted the distributor curves in the Blue Book. 

I've switched from using ported-vacuum to manifold, with better results. 

I apologize for spreading misinformation.  

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So the culprit seems to have been a bad float/needle and seat. I did end up taking out the emissions gas valve thingy.  I hooked the pump directly to the carb.  There seems to be a lot of pressure after the car shuts off.  I thought I had it licked when it cleaned out the carb, but no, after a couple of min the bowl would fill up and start to overflow into the primary.   I  do have a carter rotary pump as well as a canister filter along with a fuel pressure regulator that I am in the process of installing. I found out that I need 5/16 line rather than 3/8, so I am hooped for today. 

"Goosed" 1975 BMW 2002

 

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If you are in for buying stuff, get a 10mm phenolic carb spacer. If the carb is boiling up and percolating fuel then you need to combat the heat in the carb when standing. When running the gas atomisation naturally tends to cool the carb (hence carb icing in some cases) but when you stop the heat soaks into the carb. 

 

This will ill do more to fix this issue than swapping out the fuel pump. 

rtheriaque wrote:

Carbs: They're necessary and barely controlled fuel leaks that sometimes match the air passing through them.

My build blog:http://www.bmw2002faq.com/blog/163-simeons-blog/

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Ok I was thinking last night. I don't have the solenoid attached to the carb that stops dieseling.  I wonder if that would stop the flow after I shut off the car. I guess it would eventually fill to the point where it would come out the secondary. 

 

Thoughts? 

 

"Goosed" 1975 BMW 2002

 

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14 hours ago, Dudeland said:

So the culprit seems to have been a bad float/needle and seat.

 

could you elaborate on this?

     DISCLAIMER 

I now disagree with some of the timing advice I have given in the past.  I misinterpreted the distributor curves in the Blue Book. 

I've switched from using ported-vacuum to manifold, with better results. 

I apologize for spreading misinformation.  

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