MG MGB and MGB GT Tech Talk
Well, it's urgent to me. I am looking down the throats of my Weber downdraft 32/36 carb. When I pull on the throttle cable, only one of the throats is opening up. The butterflys on top are all the way open.
Shouldn't they both open up?
Many thanks O wise ones!!
This is a progressive carb and the secondary won't start opening until the primary is about 2/3 open
It's progressive. The larger 38mm throat will not open until you're really pushing it. It's a fuel economy measure.
That's why (some say) the Weber stumbles off the start where the SU's don't. I have a Weber and it suits my driving. And as JDW says, "set it, and never touch it again."
There is really a lot of Weber tech information on the tech section here and on some of the private sites linked on the tech page.
Some throttle cables are never adjusted so that the second barrel opens -- another reason for the poor performance reputation of the dgv.
So you got the throttle throat question answered. But you said the ones on top (choke butterflys) are all the way open? Is the car hot? if it's hot ok, if it's cold, they should be closed. Maybe that's why your choke isn't working. If it's cold they should be almost all the way closed to allow more suction though the choke valve (meaning higher mixture of gas to air). if it's hot then disregard this .
take your air cleaner off. with engine cold look at the top flys. they should be closed. As the car warms up they should open more and more gradually until they are all the way open. If this doesn't occur than something is amiss in the choke portion of that carb.
That's the biggie Dennis. I had tto do a slight bend in the pedal linkage to get mine to open fully. Now you can hear it and feel it when the 38 opens up.
John and Jim
I'm looking at buying the weber downdraft from Brit-Tek on the 11th... Gotta wait for the army to pay me mo money. Are you happy with them? anything I should know about? anything extra I need to worry about ordering that you found out about?
thanks!
Not happy so far, but I am a rookie. Let's see what the experts tell you.
