Idle raises when warmed up?

[brads70]

Hi all! 
What causes this?  When it's cold I feather the pedal for a minute or two then it runs on it's own at about 7-800 RPM's then when the temp gets up it goes to 1300 or so? When I put it in gear it's fine ( about 800 or so)
Vacume leak? I've looked but can't find one? Everything is new?
451" , auto , new 850  quick fuel carb.  Dizzy vac advance is hooked to manifold vac.
air fuel gauge stays pretty constant...?

[Jamiez]

Once it's running around 1300 and warmed up, if you blip the throttle does it drop?  Mine does the same when it's running on the Fast Idle, I have to blip the throttle to get it disengaged and running on the curb idle.

[brads70]

Once it's running around 1300 and warmed up, if you blip the throttle does it drop?  Mine does the same when it's running on the Fast Idle, I have to blip the throttle to get it disengaged and running on the curb idle.

No tried that. Idle drops when I put it in gear. Tried pulling the throttle down by hand at the carb but no change. No choke on carb or provisions for one.

[Jamiez]

I would check to see when it's running fast I would check to see if it is resting on the fast idle stop or the curb idle stop. Or even just adjusting the fast idle stop to be higher and see if it climbs higher.  Maybe something is not disengaging correctly.  Beyond that you've exhausted my extremely limited engine knowledge  

[brads70]

This is the carb. 
http://www.quickfueltechnology.com/carburetors-q-series/q-series-carburetor-850cfm-drag-an.html


camcard.....   http://www.lunatipower.com/CamSpecCard.aspx?partNumber=60312

[jimynick]

Brad, it's possible that, lacking a choke, the throttle blades have been set further open to crutch the lack of choke enrichment and that extra fuel, once the engine warms up, results in the fast idle. Does it idle, in neutral, at 7-800 when warm or does it need the drag of the trans to hold it down?

[brads70]

Brad, it's possible that, lacking a choke, the throttle blades have been set further open to crutch the lack of choke enrichment and that extra fuel, once the engine warms up, results in the fast idle. Does it idle, in neutral, at 7-800 when warm or does it need the drag of the trans to hold it down?

Idles high in park and neutral ( auto) in gear it's fine.

[jimynick]

I'd try setting the idle speed at say, 800 when warm and see what it does when cold. You may have to keep your foot on it a bit longer at first because of the lack of choke, but that's the price to be paid with no choke. You could raise the idle speed a bit, but the bang going into gear gets lame real quickly. 

[jimynick]

Nearly forgot- I went and saw Dean Albonese today. He says you're a great lad! Ian

[HP_Cuda]

Brad

You are gonna drop about 200-300rpm when putting it in gear just by putting load on the motor.

No choke on this one makes me think it has to do with air fuel mixture once she gets up to temp. Now I remember you changed the metering plate not long ago so maybe that has something to do with it? How about your throttle setup, how are your springs setup for the throttle?

So to get this straight - cold and feathered to start stays at 800 rpm out of gear but once it's warmed up it climbs to 1300rpm?

I can't blame you for not getting a choke, I freaking hate them and have been a pain in my arse ever since I bought my first Holley.

B

[brads70]

No choke on this one makes me think it has to do with air fuel mixture once she gets up to temp. Now I remember you changed the metering plate not long ago so maybe that has something to do with it? How about your throttle setup, how are your springs setup for the throttle?

So to get this straight - cold and feathered to start stays at 800 rpm out of gear but once it's warmed up it climbs to 1300rpm?

yep you got it straight.  No I just changed the jets and power valve in the metering block. Adjusted the airbleeds using an airfuel ratio gauge.

I'd try setting the idle speed at say, 800 when warm and see what it does when cold. You may have to keep your foot on it a bit longer at first because of the lack of choke, but that's the price to be paid with no choke. You could raise the idle speed a bit, but the bang going into gear gets lame real quickly. 

  Yep that's what I did.

Nearly forgot- I went and saw Dean Albonese today. He says you're a great lad! Ian

Ya he is a nice guy! Wish we lived closer he needs to get moving on that Cuda of his!

[ek3]

check the initial timing to see if it is to advanced. do you know your dist. settings. ie. initial timing point, total timing point [ the curve]. when the engine is hot, can you drop the rpm's with the adj screw? or, is  the screw all the way down .  if its all the way down , with the eng. - hot - and running, retard the dist. a few degs.

[brads70]

check the initial timing to see if it is to advanced. do you know your dist. settings. ie. initial timing point, total timing point [ the curve]. when the engine is hot, can you drop the rpm's with the adj screw? or, is  the screw all the way down .  if its all the way down , with the eng. - hot - and running, retard the dist. a few degs.

Dizzy is set at 36 all in, yes I have adjustment on the idle screw on the carb. I have it adjusted so it idles at 800 or so in gear when hot.

[422STROKER]

Any specific reason why you are using manifold vac instead of a ported vac source?  Try disconnecting the vac line and see what it does.  I idle at 900 in pk and it drops to 750ish in gear with my set up,

Tom

[brads70]

Any specific reason why you are using manifold vac instead of a ported vac source?  Try disconnecting the vac line and see what it does.  I idle at 900 in pk and it drops to 750ish in gear with my set up,

Tom

I'll try that Tom, Thanks!