Loading up when cold

[59bluesilver]

I think I finally have the correct jets/rods and idle mixture screws set, it seems to run & idle well. Gets about 16 mpg. When the engine is cold, the choke seems to be working, butterfly closes and it fast idles at 1200 rpm. But after about 10 to 15 seconds seems to be loading up. The engine slows down almost to the point of dying and will run rich like that until throughly warmed up, then I clear it out and it runs pretty good. Checked all my choke settings, seems right. What can be causing this? Idle mixture screws, jets/rods, choke, what?

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[Jeffs68]

Have you tried adjusting the fast idle screw to bump up the engine speed a bit?

The one on the primary shaft under the choke assembly on the passenger side.

[Cliff Ruggles]

What is the carburetor number?

Sounds like you need to adjust the choke pull-off to unload the choke flap to a more ideal angle at start-up.....Cliff

[59bluesilver]

Cliff,
The carb # is 7043207. I checked the vacuum pot and it's working. Not sure if it's set right, though. How do I do that?

[Cliff Ruggles]

Setting the choke, pull-off, etc is fairly easy. On those early carburetors it involves bending linkages.

First you must make sure that the choke flap fully closes when the throttle is depressed (cold engine).

Second apply vacuum to the pull-off and make sure that it unloads the choke flap.  There is a factory specification for each carb number, but basically it will need to open far enough so the engine doesn't run rich, and not so far that it doesn't run lean, when first started.

You also have to set the fast idle speed with the fast idle cam in the highest position.  Once again there is a factory setting listed for each unit, but basically it must be fast enough so the engine is happy, which in most cases is around 1500 to as high as 2000rpm's.  I'll add here that depressing the accl once drops the cam (in most cases) to the next lowest setting, which is usually around 1000-1200rpm's or so.

So even if we are not armed with all the factory settings from literature pertaining to your  carburetor number, one can still successfully set the choke unloaded angle and fast idle speed simply by doing some testing.  It is always best to work quickly, and it may take several sessions to find the most ideal settings, but once correctly set those older choke systems are dead solid reliable......Cliff