• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Weber help needed...

Share this page

lbc_newbie

lbc_newbie

Jedi Warrior
Offline
I hope you all can help, as you usually do. I had to swap my SUs out for my Weber DGV 32/36 and it is exhibiting the same problems I encountered prior to rebuilding my engine. The carb has been rebuilt per the Weber instructions, but I question some of the components that were not in the kit. Currently, I get to 2800 RPMs and the engine dies. Choke or no choke, nothing keeps is running above this RPM. The components NOT in the rebuild kit are the emulsion tube and the power valve. Can either of these cause this problem?
 
so did you have the same problem with the SU's?


m
 
If not ignition related, I'd guess insufficient fuel delivery due to dirty filter somewhere. Do you have an electric pump? If so, run it into a can for 30 seconds to check the flow. Emulsion tubes or power valve issues would not seem indicated to me. Can you rev it beyond 2800 rpm sitting in the driveway (no load)? How do the plugs look? I recently went back to SUs and ditched the Weber and I'm happier (so far). Sold the Weber and intake on ebay for $275 (and shipped it to WA, not you I hope?). I say sell the Weber and such, use the money on the SUs (if needed). IMHO
 
I did not have the same problem with the SUs, but I could not get them tuned. They were of "unknown" origin and may have been mis-matched, so I plan on rebuilding them this Winter.

The Weber will not even run with a load on it....this is just sitting in the shop and revving the motor. Electronic fuel pump with all new filters. Fuel delivery was fine with the SUs. I heard somewhere that a fuel regulator should be used with a Weber, but never really confirmed the info. Could it be float related? I also have the engine bored .030 over and a street/performance cam. I plan on re-jetting this if I can ever get it running. I'll need some advice on that also.
 
Floats sound logical..


mark
 
lbc_newbie said:
The Weber will not even run with a load on it....this is just sitting in the shop and revving the motor. Electronic fuel pump with all new filters. Fuel delivery was fine with the SUs. I heard somewhere that a fuel regulator should be used with a Weber, but never really confirmed the info. Could it be float related? I also have the engine bored .030 over and a street/performance cam. I plan on re-jetting this if I can ever get it running. I'll need some advice on that also.
Click to expand...

before you do anything fuel related, try this - take off the air cleaner and restrict the air intake - then see if it revs. I have had these exact symptoms twice and each time it was too much air. 1st time - the carb was too big (HS4 - should be an HS2) - there is now a small plate across the carb intake. second time, needed to re-tighten the manifold and the carb mount.
 
The Weber likes a little more advance than the SU"s you’re experiencing a common setup symptom. Also I agree with checking the float level I had best luck with a slightly lower than prescribe level. Mine at 24 -2800 hundred can’t be sure any more exactly where, would go lean during transition from the idle jet circuit. Here’s a link to the best info I have found on setting up the DGV.
And yes you do want to regulate the fuel pressure 2-3 PSI.
If it is in fact running out of fuel at 2800RPM you may want to take out the primary jets one at a time as they are different sizes and make sure the passage and the jet is clear. https://dimequarterly.tierranet.com/articles/tech_weber_tuning.html
 
Once when I was trouble shooting a Weber I ran it to the point of starving and shut it down then checked fuel level in the bowl. I also had one that had me puzzled until I realized the venturi tube (thing that sticks out into the throat) had come loose and rotated itself around and was not pointing down into the carb anymore. Drop of loctite solved that one (after many hours of hair pulling).
 
jvandyke said:
Once when I was trouble shooting a Weber I ran it to the point of starving and shut it down then checked fuel level in the bowl. I also had one that had me puzzled until I realized the venturi tube (thing that sticks out into the throat) had come loose and rotated itself around and was not pointing down into the carb anymore. Drop of loctite solved that one (after many hours of hair pulling).
Click to expand...

Hmmm DGV Diverted Gas Venture tube could it be you stumbled on the true source of the acronm?
 
I'll go for adjusting the float tomorrow and report back to you all. Thanks for all the suggestions. Is there any consensus on the fuel regulator? The articles I've read have suggested 2.5 to 3.0. Is there a reputable gauge on the market? ebay returns thousands of them. They all look like rice burner junk.
 
I've read Webers are happy to 4 psi. Wouldn't too much fuel pressure and overfilled bowls be indicated by fouled plugs? I think the cheapy fuel regulators are okay. I had one go flaky and restrict fuel way too much though (symptoms were hesitation and "bucking" at extreme load conditions). I took it apart and it was simple enough, never figured out what was wrong with it but I put on another and my issues disappeared immediately. Still I'd hesitate to shell out the big $$ for a Holley one.
 
OK, I finally had some time to spend on the car. I took the Weber apart and verified everything is to spec on the carb, per the Weber set-up guide. Everything is standard on the carb. This leads me to believe it's a fuel issue. What should I expect, as far as output goes, from my electric fuel pump? If I held a gallon gas can to the line, how long should it take to fill? Any other ideas on measuring this?
 
+1 for fuel pressure regulator. I know it initially seemed counter intuitive to me that fuel pressure issues could creep up in such bizarre ways but it does. I once had a car that would die on sharp left turns or hard breaking. Turned out to be a fuel pressure issue. I also had a fuel pressure issue with the weber on my Midget when used with an aftermarket fuel pump. A regulator solved all of my problems in both cases. The counter intuitive part for me was the thinking that the float bowl should shut off the fuel when the bowl is full but the reality is that it can't when the pressure is too high.

JACK
 
I'm not sure what type of exhaust or intake manifold that you are running, but, I have the stock exhaust with the Pierce intake and they have a different thickness at the flange. I had to manufacture a washer/spacer that was different heights to make sure I did not have any leaks. No idea if that is your problem, just throwing it out there. If you pull it off, replace you brass nuts. Mine were 8mmx1.00.

Mike
 
Edward -

I use the 32/36. Going on your belief that everything is up to snuff. Look at fuel. I am also using the Holley reg (ebay for $30 ish)

https://cgi.ebay.com/ebaymotors/Holley-12...sQ5fAccessories

Look at that first. I'm making some assumptions - car gets flakey after 10 - 15 min of use (time for bowls to get overwhellmed). Does this happen running in the driveway vs. actual use?

As for Weber or SU's - it depends on whom & where can get the most help from. For me in Cleveland - Weber's were the answer. Most custom shops know these IF you don't have a gearhead buddy (I have lots). None knew the SU's.

My strong vote is the reg. Might want to do a facet fuel pump wheile your at it and be safe for many years.

Keep us posted.

Geo
 
I'm still amazed by the simplicity of the SUs, to me they are far easier to deal with, but I don't have much experience with either.
 
Back
Top