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Discussion Starter #1
The timing is bang on 6 degrees TDC. The 2 barrel carb was rebuilt and seems to be working fine. The ignition system is using a dual-diaphragm distributor including a distributor vacuum control valve which also seem to be working fine. The intake manifold has vacuum connection the other is capped.
The rpm continually cycles between 600 and just above engine stall while idling. When cold, the engine will stall unless gas is applied when the rpms drop. Any suggestions would be appreciated on how to trubleshoot this problem.
Thanks!
Karl
 

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Maybe its been rebuilt but your symptoms sound like the carb has not been adjusted properly. Maladjusted idle mixture will make the engine stall, run poorly at low speed and/or the idle speed can vary up and down as the engine almost stalls, then recovers and makes another gasp at running. Adjust both of the idle mixture screws for max idle speed, one at a time, and see if the problem doesn't improve. That is done with everything warmed up.

If it doesn't run good when cold that is choke adjustments which are somewhat complicated but should be described in your shop manual.
 

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Discussion Starter #4
Thanks for the tip Ivy66GT. It makes sense and I will try to adjust the carb. Just as a side note, the engine starts fine but it has to be kept going with the gas pedal until it warms up a bit. The cycling rpm continues even after the butterfy valve on the carb is fully open.
Thanks for your help!
 

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Probably a carb issue. But first I'd see how it responds to a little more initial timing. I run about 12 degrees, no problem.

Just make sure it doesn't knock under load (like driving uphill at low rpm).

Note: Your initial timing is just a starting point. Total timing is much more important -- typically arrives somewhere around 3000 rpm.

If you've got an adjustable vacuum advance on your distributor, then you can fine-tune how much & how quickly your vacuum advance occurs.
 

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Discussion Starter #6
Retired Boomer, thanks for the tip. I will try and adjust the carb and, if necessary, play with the timing this weekend. Let's see what happens.
Thanks for the suggestions!
 
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