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first let me say; this is a 2100 automate from a 260 v8 on a v6 buick jeepster. Common upgrade.
Here is my problem.

Rebuilt carb last year and it ran fine. Now when it is cold everything is great, runs strong. After about 20 minutes, it suddenly bogs down. It feels like its overloaded with fuel and it starts blue smoking. You can stomp the pedal and it will.blow a cloud of smoke and clear.up.some, but when you come back to.a.slower town speed, it bogs up again. Could.be a timing thing , but I have it set to spec. Not sure. Any thoughts?
 

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1965 C-code Coupe, Silver Metallic Blue, 3-speed toploader, 3.00 rear
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Blue smoke is running rich, but can also be incomplete combustion.

I had a surging and bogging, and it turned out it was my condenser leaking current from my points ignition and I was losing spark. Does it have the original points or electronic ignition?
 

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I would consider pulling the carb off and checking that your power valve is all good. It’s possible that sitting over the winter caused the diaphragm to crack, or it may have varnished up and become stuck open/partially open. Today’s alcohol/gas blends are hard on those rubber parts as well. It may be allowing fuel to flow fully enriched at all times, instead on when vacuum drops and you are trying to accelerate. This would cause a rich condition, especially right off idle. Fully open throttle blades could eventually compensate, but you’d have basically flooded it prior to that.


You may have a power valve with a spring tension that’s not fully compatible with your engine too. Look for one that’s approximately half your idle vacuum value (and/or add one or two, you’ll be in the ballpark.).

if this makes no difference, you could try smaller jets and read your spark plugs to see if they are appropriate.
 

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BLUE smoke is typically oil burning. BLACK smoke is typically rich fuel mixture. Since you have a manual choke we can eliminate that right off the bat. Have you pulled the plugs and looked at them? Is there oil in the PCV hose? Is the ignition system in good shape? So many things could be contributing to your issue.
 

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When it starts bogging down, look down the carb throat. It might be percolating and dumping fuel.
 

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What Hemikiller said. Do you have a spacer under the carb? If not, that's probably your problem.
 
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