'73 440 adjusting idle Speed

[Lycidias]

Hello out there!

I'm embarrassed to ask something so simple, but I just couldn't figure it out. The 440 is my first carburetor and US engine...how do I adjust the idle speed? I've only read everywhere "you have to set the idle...", "set the idle to 650-800"...but I couldn't find HOW to do it, either on the internet or in the manual.

Is this simply adjusted via a screw on the throttle cable or via the carburetor?
My engine runs a little too high and I want to lower the idle a bit.

The idle speed went up after I corrected the ignition timing from +5 to ~ -12 BTC.

greetings Manuel

Maybe you can hear it in this video:
"""
There it is running... beautiful ! Sounds like a car should sound. And that's just Y pipe single exhaust. I am planing to buy a 2,5" Dual exhaust from TTi.


"""

 

[Snotty]

There is a screw on the throttle, right where the accelerator cable connects to the carb. It rests on the choke valve/butterfly/thing. Ha!

It appears in each of these pictures, if you know where to look. In the third one, it's right underneath the green return spring.

Good luck!

 

[Lycidias]

Perfect. Just tried it: runs (cold) @950-1100. I will check this warm and with build in rec Counter.

 

[CBODY67]

Seems like the idle speed is supposed to be closer to 700 rpm hot. Should be a decal near the radiator with tune-up specs on it (hot base idle speed, ignition timing, spark plug gap), if it is still there.

For many Chrysler Factory Service Manuals and Chrysler MasterTech Videos, www.mymopar.com . Some of the service manual listings get a little "thin" past about 1972. Free downloads.

Take care,
CBODY67

 

[Big_John]

Thermoquad manual: https://www.thecarburetorshop.com/Service_Carter_Air_Bled_Thermoquad.pdf

Look at the illustration on page 3 for the fast idle and curb idle speed adjustments. Fast idle being the idle speed when it's cold and the choke is on. Curb idle is warmed up with choke off.

Since that's a PDF, you should be able to download and/or print out a copy for yourself.

 

[Boydsdodge]

Thermoquad manual: https://www.thecarburetorshop.com/Service_Carter_Air_Bled_Thermoquad.pdf

Look at the illustration on page 3 for the fast idle and curb idle speed adjustments. Fast idle being the idle speed when it's cold and the choke is on. Curb idle is warmed up with choke off.

Since that's a PDF, you should be able to download and/or print out a copy for yourself.

Page 3 Fig 1. Just trying to help narrow it down for ya.

 

[cbarge]

I recommend using a vacuum guage when adjusting the idle speed.
With the timing adjusted and then idle speed, you should have 18 inches or more of vacuum.
Hope this helps.

 

[Lycidias]

Thank you!!! I will work through this advices!!

I habe the '73 manual but couldn't find it there.

The decal is there.

 

[cbarge]

Thank you!!! I will work through this advices!!

I habe the '73 manual but couldn't find it there.

The decal is there.

View attachment 611116

The decal is a good baseline to start..but it is not the bible.
With today's ethanol fuels and octane levels being very different compared to 50 years ago, the engine may want more timing or fuel or both.
Thats where the vacuum guage comes in.
Time and age, one mixture screw nay need more or less adjustment than the other to make the engine run smooth.
Test and tune, road test for any ping, test and tune!
Hope this helps.

 

[cbarge]

BAsed on my experience with Thermoquads on todays gas, you may have to increase the shot at the accelerator pump to avoid any part throttle dead spots

 

[Lycidias]

Well I suppose even the gas Europe/USA is different. We have at least 95 Oct (E5) to 102(?) without E addition. It runs good on 95. I have just few time for my cars but I will do the adjustments as soon as possible...here ist Gas 7,73$\Gal...

 

[330dTA]

Lycidias, your gas is cheap. The medium price in Helsinki today for 98 octane is 2,05 euros per Liter. That’s $8,75 per gallon at today’s exchange rate. (I just poured 56 liters in. LOL.)

 

[cbarge]

Lycidias, your gas is cheap. The medium price in Helsinki today for 98 octane is 2,05 euros per Liter. That’s $8,75 per gallon at today’s exchange rate. (I just poured 56 liters in. LOL.)

Here in Ontario Canada we are not far behind Europe at 1.95.3 per litre!

 

[Boydsdodge]

There is also a very small screw in the centre of the carb that adjusts the height of your primary fuel needles. Called the step up piston, in fig 9. That helps with off idle and idle richness if it has been set up wrong.

 

[Lycidias]

Ok.

I am going to adjust this one first

 

[Knebel]

Yikes and I'm complaining about 4.66/gal. But hoestly, it used to be under $3 before the war. 3 weeks ago I stopped in Rachel, NV and gas was 5.99/gal there..dang aliens lol. Anyway, If it helps you, send me a Private Message and I'll explain in Deutsch if that helps better! Its a lot easier than tuning a SU or weber or anything like that. Curb idle is a good start, make sure its off the choke!

 

[Snotty]

When talking about gas prices, all of us in the US need to remember, that our prices do not include the large taxes many European and other Countries have. The price per barrel of oil is only the starting point.

 

[cudamark]

Our California state taxes along with federal taxes are nothing to sneeze at either. The best price I can find currently in my area is $4.70/Gal.

 

[Lycidias]

That's still far away from 8-9 Bucks a Gallon

 

[Lycidias]

Got it down to 23,5L/100 = ~10mls/gal. Wich is okay cause I didn't drove on the highway.

Idle speed is still to high, didn't had time to fix it.

When talking about gas prices, all of us in the US need to remember, that our prices do not include the large taxes many European and other Countries have. The price per barrel of oil is only the starting point

Here ~48% of the gas price is taxes.