1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Weber 48 IDA questions.

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Old 09-25-15, 09:35 AM
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Weber 48 IDA questions.

Hi guys, I'm looking for how you set your webers up. Emulsion tube specs, idle jets, etc. Also where all of these parts are, I've tried googling and I cant find the parts, only the part numbers in an exploded view.

Thanks,
Nick
Old 09-25-15, 10:34 AM
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cannot find the parts to buy, or cannot find the parts physically on the carb?

parts are pretty easy, on the west coast we use these guys Authentic Weber Carbs, Manifolds, Conversion Kits, Accessories and More! we get 1-2 day service from them. you east coast guys like to use that alfa1750 guy on ebay, he's in italy.

as far as which jets to buy, it really depends on the engine/intake/exhaust combo. additionally the jetting interacts, so there is more than one combo that will work.

generally though, idle jet will be 55-65, a stock 12A will be the smaller, and the big port 13B's will want the larger one.

for a 12A i like the E7 emulsion tube, and the E8 for the 13B. the F11 is for a vw bug, people make them work, but they should have thrown them away and used anything else

the main jet sort of correlates to hp/efficiency - the air fuel ratio and fuel pressure. i've seen 6 port engines and P port engines run the same 230 main jet, but the AFR is different, and power is different.

just in general, the stock 12A will be around a 180, 13B might be 200, a 6 port and P port 13B will be in the 230 range.

the air corrector rule of thumb i think is to subtract 50 from the main jet, and then you will want to try a bigger and smaller, as it fine tunes the transition between the idle and main jet
Old 09-28-15, 07:33 AM
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I have no idea what parts I'm looking at when I look at the carb. I've adjusted what I thought was the idle screw, and nothing has changed. The engine is also a street-port. Should I think about changing the venturi's and everything so I can daily this better in winter?
Old 09-29-15, 06:31 PM
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Also, I want to reseal the point where the carb meets the intake, is there a gasket for the metal risers or do I have to use a sealant? And if so, what kind?
Old 09-30-15, 10:00 AM
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48 IDA
Old 09-30-15, 10:59 AM
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I would use 40mm chokes a 3mm needle and seat emulsion tubes F2 air corrector jets 130 and main jets 185 to 195 Idle jets 65 this is for a 12a a 13b the same except for mains 190 to 210 for street port only
Old 09-30-15, 09:58 PM
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Thanks J, is it just me or do the idle speed screws take some extra force? Also, clockwise is increase and counter clockwise is decrease? Now, what else is there to adjust the idle? just the jets?

WJM, is that for winter or for summer?
Old 10-01-15, 07:43 AM
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Originally Posted by WJM ROTARIES
I would use 40mm chokes a 3mm needle and seat emulsion tubes F2 air corrector jets 130 and main jets 185 to 195 Idle jets 65 this is for a 12a a 13b the same except for mains 190 to 210 for street port only
have any idea what do use on a 4port 13b with a 48ida half bridge full dual rb exhaust?
Old 10-01-15, 09:07 AM
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Originally Posted by Sh00bs
have any idea what do use on a 4port 13b with a 48ida half bridge full dual rb exhaust?
The same jetting I gave will work fine on your motor
Old 10-01-15, 09:13 AM
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Originally Posted by NLPerformance
Thanks J, is it just me or do the idle speed screws take some extra force? Also, clockwise is increase and counter clockwise is decrease? Now, what else is there to adjust the idle? just the jets?

WJM, is that for winter or for summer?
All year round should not need to change but remember we don't get snow here in Aust. Idle screw in [clockwise ] leans out. Screw out [counter clockwise ] makes richer. There should be an idle screw at one end of the throttle sharft
Old 10-02-15, 07:11 AM
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Originally Posted by WJM ROTARIES
All year round should not need to change but remember we don't get snow here in Aust. Idle screw in [clockwise ] leans out. Screw out [counter clockwise ] makes richer. There should be an idle screw at one end of the throttle sharft
good stuff. thanks for the info mate
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