Question on electric choke

[spstan]

Have a Holley 4175 spread bore with electric choke on a 440 motor. Changed the timing chain and the car starts right up and runs smooth for a minute or two (even with a load on) and then it starts to falter and the idle with a load on becomes rough. I'm suspecting the choke needs adjustment but I don't know which way (richer or leaner) and to what degree (one or two notches? ). Or maybe its not the choke at all. Any ideas on why it goes from smooth to rough idle in a minute or two? Paul (pictures below)

 

[CBODY67]

As with a divorced choke thermostat, you can probably go one notch leaner and not cause any problems. ALSO, with the carb/engine at ambient temperature of about 65-70 degrees F, with the fast idle cam at "full fast idle" and the choke plate free to move as it desires, loosen the outer three thermostat hold-downs and rotate the thermostat enough to just barely close the choke plate. "Barely" is the key word. Then tighten the retention screws. It is just fine if you end up a notch leaner than the carb came adjusted! That's how I have my 4175 set (on my Camaro 355).

In cooler weather, when the ambient temps are consistently in the 65 degree F range, recheck, for good measure.

Just my experiences,
CBODY67

 

[spstan]

As with a divorced choke thermostat, you can probably go one notch leaner and not cause any problems. ALSO, with the carb/engine at ambient temperature of about 65-70 degrees F, with the fast idle cam at "full fast idle" and the choke plate free to move as it desires, loosen the outer three thermostat hold-downs and rotate the thermostat enough to just barely close the choke plate. "Barely" is the key word. Then tighten the retention screws. It is just fine if you end up a notch leaner than the carb came adjusted! That's how I have my 4175 set (on my Camaro 355).

In cooler weather, when the ambient temps are consistently in the 65 degree F range, recheck, for good measure.

Just my experiences,
CBODY67

CBO; "leaner" - meaning I rotate the plastic cap clockwise? Paul

 

[CBODY67]

CBO; "leaner" - meaning I rotate the plastic cap clockwise? Paul

I believe that is accurate, but check for the casting arrows indicating "lean" and "rich" on the thermostat housing to make sure.

CBODY67