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MG MGB Technical - WEBER PROBLEM

car has the moss weber setup
while riding at 50 mph the car suddenly lost power,pulled to the side of the road where she idled perfectly.....when i tried to move she died....out of gear, when i applied gas she would rev to 3000 easily and then die...after much fiddling i got it to run so i could get home by locking the choke in an almost closed position. (about an 1/8 inch gap) she ran great in that mode for 10 miles.
i added 3 bottles of carb cleaner to the tank, sprayed
a can of carb cleaner down the throat .. all with no positive results am open to any suggestions
rocco grillo

Rocco. Have you checked out your fuel pump and fuel filter? This sounds like a lack of fuel problem and will not be cured by adding carb cleaner to the tank, nor spraying carb cleaner into the carb. You have either a bad fuel pump, plugged fuel filter, plugged lines, stuck valve in the carb float bowl or something of this nature. David DuBois has an article on the SU fuel pump on my website, www.custompistols.com/ which should give you the pressure and flow requirements you should be seeing. Changing a fuel filter is a simple job and inexpensive. If you have good fuel pressure and volume at the hose going to the carb, then, you can pull the top cover and see what is inside the float bowl. Troubleshoot the problem in a systematic manner and let us know what you find. Then, we can provide a more focused approach to helping you solve the problem. But, what you describe is what I experienced with a clogged fuel filter. Les
Les Bengtson

thank you les
i have two fuel pumps in series, one is switchable from the dash. your reasoning parallels mine. i cleaned the filter below the bowl, changed the in line filter
my gut feeling is that a passageway is partially blocked and with the increased vacuum from the choke being almost closed sucks enough fuel to function
thank you rocky
rocco grillo

Rocco - Remove the gas cap and see if the car will run properly. If you have a plugged tank vent (either in tha gas cap for the early car and throught he charcoal canister on later cars) you will see much the same symptoms, especially when the tank has been filled tothe top. Good luck - Dave
David DuBois

david
thank you, did that she runs great with the choke almost closed......took off the top plate and blew
everything in sight with 40 psi rocky
rocco grillo

Rocky. You still need to do a fuel pressure and volume test. Two fuel pumps is a good idea. But, if the problem is an air leak on the intake side, or an obstruction between the pumps and the carb, you will have a problem. Closing the choke on a Weber will enrichen the mixture. If you have insufficient fuel supply, the restriction on the air coming in may allow you to have a mixture which will burn at a larger throttle opening. Otherwise, the mixture would be too weak to burn. Hence, the use of the choke tends to indicate some form of restriction in the fuel supply. Les
Les Bengtson

les
will look at that tomorrow it seems to me that when i ran the second pump into a plastic hose into a 5 gallon can to check if trash was in the fuel, i saw bubbles in the plastic hose, did not think too much of it at the time
thanks
rocky
rocco grillo

checked pressure, volume, all fine ....checked for bubbles going to carburetor, non there ... took top plate off and removed all jets and blew air threw them,
took out the power jet, it looked fine, accellerator pump works ok ... still idles great but under load she starves ....locking the choke plate at almost closed she runs like a champ ... so it can't be supply or pressure ... is the carb a weber 32-dgv and is there a rebuild kit available THANKS FOR YOUR HELP ROCKY
rocco grillo

Rocky, Remove the fuel/air idle screw and blow it clear. Replace the screw and seat it gently, back it out about three turns then dial it in until the engine begins to falters. Also replace the acceleration pump. The old one may be torn and or the spring broken. Vic
victor gardino

this morning i ordered a rebuild kit for the carb
i then took off the carb getting ready for the kit when it comes
WELL i took it off and inspected it prior to taking it apart ...there is a kole in the back that must be for hooking to yhe distributer for advancs
since its in the back it is invisible from all sides
it must have been plugged and somehow got unplugged
i plugged it for good
it will go on tomorrow before the ups man comes, just to prove it to me
THANKS ALL YOU GUYS, WILL POST RESULTS TOMORROW
ROCKY
rocco grillo

This thread was discussed between 26/10/2004 and 29/10/2004

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