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55 Buick super, 4bbl 322 dynaflow , poor idling and high HC


luc

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Hello car enthousiasts...

 

I m a bit stuck on the 55 super here... Ir won't run like it should...

To get the problem solved i have changed the sparkplugs, new contact points, condensor, rotor cap an rotor.

Ignition on 7 btdc

Carter carburetor is redone, new gasket set, float levels set as requested etc... Adjusted accellwration pump etc .

Engine starts good, but idles poorly on 1.7 co... And does not react any more to unscrewing idle  mixture srews from 2.5 turns out... co percentage doesnt go higher than this...

If i turn them in, Engine will stall as normal, so ports must work...

Fielpump is of the electric type, carb does not overflows...

 

Hydro carbons go to 1200 and fuel smell is there...  Rear bumper is black.

Sparkplugs to...

 

Compression test is 9 to 9.5 bar on all cilinders...

 

So i expected to find a bad gasket in the intake circuit ... I changed inlet gaskets between cilinder heads an intake manifold... All gaskets under the carburetor ar new aswel.

Detached and stuffed all vacuüm ports.... No luck...

Even checked the markings on the timing gears... Twelve teeth as shown in the shop manual...

 

Idd thing is that inlet valve starts to open at aprox 10 deg before tdc... I have found somewhere it should start to open at 25btdc... But have not found a confirmation...

 

 

The other odd thing is that the 4bbl carter has the same jets on prim and sec side... Main jets and slow idle jetd

 

Any thoughts? What do i not see here

 

 

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I would be suspect of the electric fuel pump.

The symptoms you describe indicate to much fuel.

If you can, hook up a gravity fed temporary fuel source. Like a boat can or old lawn mower tank,

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Just went through something similar on a 327 Chevy.

problem was 3 fold.

timing mark was off about 6 degrees. (Advanced) remarked at tdc and added degree tape. ( who knows how that got off in the last 60 years. Parts good.)

vacuum advance was frozen. Replaced with new.

vacuum advance was tied to ported vacuum. Tied advance to full vacuum.

Made a different engine out of it. Starts and idles perfectly. No more black smoke.

No sooted plugs.

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