Non-LSx Weber carburetor question
08-20-2009, 07:33 PM
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Non-LSx Weber carburetor question I've got a weber carb Model 34 DMSA on a '74 Fiat Spyder. I don't know jack about carbs but after looking through the rebuild manuals I was able to get the thing cleaned up and reassemble and now the engine runs.
When I punch the gas the engine hesitates then picks up steam. I narrorowed the problem down to the accelerator pump but can't figure out why its not working. The diaphragm is in good shape and the outlet passage is clear. The pump isn't drawing fuel in when the diaphragm expands. I read that there is a one way valve in the accelerator pump circuit--is this on the inlet or outlet side--in either case I've not found it yet? Other question is where is the inlet passage. There is a "accelerator pump blanking needle" installed in the upper left cavity..the right cavity is sealed. Is this where fuel come in? The reassembly process just said to screw the needle in and yet i notice the brass piece has a slight taper to it...sorta like a needle valve????
Anyways if anybody has any insight on these Weber carbs let me know.
When I punch the gas the engine hesitates then picks up steam. I narrorowed the problem down to the accelerator pump but can't figure out why its not working. The diaphragm is in good shape and the outlet passage is clear. The pump isn't drawing fuel in when the diaphragm expands. I read that there is a one way valve in the accelerator pump circuit--is this on the inlet or outlet side--in either case I've not found it yet? Other question is where is the inlet passage. There is a "accelerator pump blanking needle" installed in the upper left cavity..the right cavity is sealed. Is this where fuel come in? The reassembly process just said to screw the needle in and yet i notice the brass piece has a slight taper to it...sorta like a needle valve????
Anyways if anybody has any insight on these Weber carbs let me know.
