Tricks for low idle when cold (and no choke)

[XH29N0G]

The Idle on my engine increases considerably when warmed up, and is even higher if I run it up through the gears a few times.  I think it has to do with the build.  This means that the idle is way too low when it is not fully warm.  My carb does not have a choke.

Does anyone have a trick for advancing the idle when cold so I don't have to keep my foot on the gas for 15-20 minutes?  Maybe some sort of cable operated stop?

[c00nhunterjoe]

Sounds like some fine tuning. Whats the carb? I have no choke on my holley either and i only have to warm mine up for about a minute and its good to idle on its own. I have a cam similar to the mopar 509 in a 383.

[chargerbr549]

I don't know if you are running the vacuum advance on your distributor but it could be that you have it connected to full manifold vacuum but the engine when cold isn't pulling enough vacuum to advance the distributor but when the engine warms up it pulls enough vacuum to advance the timing a considerable amount, just a possibility. Try unhooking the vac advance and plugging it and see if that changes your high idle when its warm.

[XH29N0G]

Thanks for the replies.  The carb was a QF 830 SS. As a recent experiment, I swapped the main body for a proform annular 1050.  I see the behavior with both configurations, but the 830 original configuration has a choke so it is easier to deal with.  The controlling factor appears to be whether the engine is cold, warm, or very warm. 

I am not running a vacuum advance.  I am using an a/f gauge for tuning and think it is pretty well dialed in. I may be off base, but my guess is that the behavior has something to do with the build.  It has forged pistons and I wonder if they seal up better as it warms up.  The cam has similar lift to the 509 but not the duration. 

What I have done recently is simply to advance the idle a little on the idle set screw and then to back off once warm.  I thought it might be easier if there was another way that the throttle could be advanced a little when cold.  At one point I had a manual choke on it.  I have been wondering if I can rig an advance with a cable, but need to look at the carb more closely.

[John_Kunkel]

You might be able to rig up an electric idle solenoid to kick up the idle speed until the motor warms up, these are typically used with A/C or as an anti-dieseling solenoid.

http://www.jegs.com/shop/en/jegsdirect/748535

[XH29N0G]

That looks like an interesting option.  I was in the process of disassembling a manual choke assembly, but had not yet figured out the geometry of connecting it because the main body has slightly different tapped holes.