tuning trouble

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70dusta

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hey im having some trouble tuning my carb. Ive got black smoke coming from the exhaust and when i took out my plugs they were very black and sooty. Ive got a 318 +30 with a holley 650 i cant find a good tuning manual for the air/fuel mixture can ayone help.
 
70dusta,
How far out are the bleed screws on the side of the carb? They should only be out 1/2 to 3/4 turn from the factory. Then if this is OK then check the jetting in the carb if someone has changed the jets then jet it down, they should be 72 in the front and 76 in the rear if I'm not mistaken. If this is right then make sure that the bleeds in the top of the carb aren't clogged as this will cause a rich condition and flooding if too small or clogged. You have 4 on the front and 4 on the back, the outer most ones are the idle circuit and the inner most ones are the power circiut, the same goes for the rear. To clean the idle up you would have to enlarge the outer most bleeds .005-.008 and this should make it a little on the lean side but adjustable. Hope this helps you.


BJR Racing
 
What cam are you running? What's the rest of the engine/ignition look like?
 
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