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Need a book on Weber carbs

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Tim_Creger

Tim_Creger

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I just bought a '72 MGB with a Weber carb, and I've never dealt with this make before. Can anyone steer me towards a good reference manual that will help me identify the model and adjust it. I bought a Brooklands Weber Tuning manual, but it isn't what I expected or need (for sale cheap if someone wants a new one!). Right now I have trouble starting it and have noticed a loss in power at constant rpm on the road after 30 minutes of driving (60 mph). I'm used to a Bugeye with SU HS2 setup, and have dealt with Stromsburg single barrel carbs years ago, but I don't want to tear into this thing without knowing what I am doing, I'd to mess it up.

Thanks in advance,

Tim C.
 
If you've noticed a loss of power after some time driving, it may be that your car has an unvented gas cap. Over the years, many of these cars have had their emissions systems modified, plugged or removed and need a cap vent. Run the car for a half hour with the cap off (or loose but secured somehow) and see if that helps. If it does, drill a small vent hole in the cap.

There are two type of Weber carbs fitted to MGBs. The sidedraft Weber carb are actually pretty nice. The downdraft is simple but not exactly sporty.
 
Along with an unvented cap, perhaps an overheating fuel pump. Simple enough to check the cap first, tho.

aeronca65t said:
The downdraft is simple but not exactly sporty.
Click to expand...

And it was used on a lot of "other" cars as OEM induction. Fiat 124's come to mind.
 
Kinda funny, but with all the good and not so good reports on the 32/36 style Weber's, I would say that it's probably the most widely used conversion carburetor on the market today. I had one on my 6 cylinder CJ-7 and it was a wonderful setup, not only giving more power but used less fuel. On the other hand, I had one on my old 79 MGB and it was sick! I took it off and put a set of SUs on it and it ran like a champ. I now use that Weber as a door stop in my shop! (Mounted on a piece of wood of course). :devilgrin:
 
Thanks for the tip. The carb is definitely a downdraft, and from just looking at a lot of photos and diagrams on the internet, I have narrowed it down to possibly a 38/38 DGAS. I can't find any markings or numbers on it to give me a clue as to whether that is correct or not. The gas vapor canister has been removed, and from what I can tell, no other venting was provided for the tank, so it is very possible I have a gas cap vent issue. I'll look into that, the symptoms certainly make sense.

This carb has an electric choke, something I didn't even know existed before I bought this car. Would the Haynes book mentioned in one of the replies cover those doohickies?
 
That is close, but not quite the one. I can tell the two venturi ports are identical size, not the progressive style of a 32/36. This is what looks the closest to what I have.

38 DGAS

Tim
 
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