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Discussion Starter · #1 ·
Can anyone tell me what the idle jet size should be for a 33 1.7QV running 40IDF carbs? Cheers John.
 

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Discussion Starter · #3 ·
Just checked

the carb, it's running a 50 idle, 140 main, 200 air correction.
 

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Discussion Starter · #4 ·
Idle jet size

Should I go to 55's on the idle jet, or 52's as the next step up from the 50's?
Some Weber sites only carry the 55 as the next step up, but I noticed that 52 is available as well.
The reason I am changing is because I can't get the adjustable fuel mixture jet to run at the 2 1/2 turns out, it won't run at less than 3 1/2 turns. The Weber help sites suggest increasing the idle jet, but how far?.
 

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Discussion Starter · #6 ·
Idle jets to small

cause this apparently. By richening the needle this compensates for the lean idle jet, but this also makes you have to increase the idle stop to make it idle at anything like the right speed. So fuel consumption suffers as you are running a slightly open throttle over what would normally be the case. Also the engine hesitates just above idle speed on take off as it overcomes the leaness, or something like that. Of course I stand to be corrected.
 
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