Idle control on 66 Hemi

AR67GTX · Jan 23, 2021

Trying to get familiar with this 66 Satellite Hemi I recently purchased and what’s - what. I know it has an early 67 block and has what seems to be a mild hydraulic cam so there are some originality issues with the car. The carbs seem to be generally correct - 4139 & 4140 with C6 dates.

my question is in reference to what seems to be a lack of conventional curb idle adjustment screw. There’s no cam w/tang on the shaft where the curb idle screw would bear and it looks like the carb body has not been drilled out and threaded for a curb idle screw (it does have a cast hole or partial hole). So is curb idle set strictly with the air bypass at the front of the carbs between the idle mixture screws?

If so, should both carbs be adjusted equally to achieve the desired idle speed?

thanks

gtx6970 · Jan 23, 2021

Ye, and yes .
thats how I set mine. Ive tried to keep both front and rear somewhat equal in number of turns

More details on the car please.

I have a 66 hemi Satellite and have been keeping track of them as a part time hobby , options , colors etc etc

Edit,
never mind,,,,,,I see you bought the black on black 4 spd car

AR67GTX · Jan 23, 2021

Thanks - that clears that up.

I don't know much about the car as the dealer would not provide prior owner information per some privacy agreement and their messages to the prior owner have not prompted him to contact me.

It's a 66 Satellite originally dark blue with vinyl top but now all black. Car is 4 speed without PS/PB. Appears to have had a few options like radio/clock added at some point. Supposedly came out of a small (10 +/-) Mopar collection and bought by Legendary a year and half ago or so. Block is a fall 66 casting so 67 vintage. Has fender tag but no other docs provided with car. I haven't gotten around to pulling the rear seat yet to look for a broadcast sheet. Car seems very straight and solid but not show car. Probably painted a few years ago and partly restored but sort of slapped together towards the end and been sitting for some time either in somebody's shop or at Legendary.

If this description sounds familiar to anyone who might know of the car I would be interested in any leads to prior owner. It's a Lynchburg MI car.

https://www.amazon.com/photos/all/g...c1-4e1c-b3b7-4b44cf3da6d8&pf_rd_i=13234696011

gtx6970 · Jan 23, 2021

They have had that car for quite some time. I know for sure at least a year . I saw it advertised when I started looking. But the 4 spd killed it for me
I didnt know it was a color change car. Im sure that factored into a delayed sale .
car looked absolutely killer in photos

Congrats

These photos have me thinking I want to put red line radials on mine this spring .

AR67GTX · Jan 23, 2021

I think from the registration they had it from late 2018. I had been following it for awhile as had a few other people. Can’t say the color change isn’t an issue but I’m a sucker for a black car so I was OK with it.

Jerry Hall · Jan 23, 2021

On stock 66-67 carburetors there is no idle adjustment screws or air mixture adjustments on the rear carburetor. There are air mixture adjustments on the front carburetor. This applies to 4-speed cars. I can't be certain about automatic cars. In a previous thread that is why I was looking for the correct throttle bracket for one of my 67 GTX 4-speed Hemi cars. It had idle problems that I determined was coming from a make shift throttle bracket. With the correct throttle bracket adjusted correctly you can attain a idle rpm of 750-800 and still have wide open throttle all with the throttle cable.

Fran Blacker · Jan 23, 2021

Try looking under drivers side front seat where carpet overlaps. Mine a St Louis car and read here Lynch road wasn't good with BS's. Good luck.

AR67GTX · Jan 23, 2021

Jerry Hall said:
On stock 66-67 carburetors there is no idle adjustment screws or air mixture adjustments on the rear carburetor. There are air mixture adjustments on the front carburetor. This applies to 4-speed cars. I can't be certain about automatic cars. In a previous thread that is why I was looking for the correct throttle bracket for one of my 67 GTX 4-speed Hemi cars. It had idle problems that I determined was coming from a make shift throttle bracket. With the correct throttle bracket adjusted correctly you can attain a idle rpm of 750-800 and still have wide open throttle all with the throttle cable.

My carbs have air bypass and mixture screws on both carbs - choke on rear only. I’ve seen sets where the front carb had sealed mixture screws but exposed on the back carb with the choke (friends 69 Hemi is like this). Matter of fact I’ve seen photos of Hemis with about ever combination of Carter’s with and without exposed mixture screws and with and without air bypass. I’m sure a lot of them have been messed with over 54 years and I wonder if the various assembly plants turned them all out alike. And then there were the CAP cars.

Jerry Hall · Jan 23, 2021

AR67GTX said:
My carbs have air bypass and mixture screws on both carbs - choke on rear only. I’ve seen sets where the front carb had sealed mixture screws but exposed on the back carb with the choke (friends 69 Hemi is like this). Matter of fact I’ve seen photos of Hemis with about ever combination of Carter’s with and without exposed mixture screws and with and without air bypass. I’m sure a lot of them have been messed with over 54 years and I wonder if the various assembly plants turned them all out alike. And then there were the CAP cars.

Can't answer that I'm only speaking of the 2 67 Hemi 4-speeds I have left.

gtx6970 · Jan 23, 2021

Im not 100% sure is this is the 1st hemi car Ive owned in nearly 30 years.

BUT,
Im pretty sure air bypass is 66-67 only.

68 and up have an actual idle screw on the lever. And mixture screws,,,, I THINK are on rear only.

AR67GTX · Jan 23, 2021

I believe that jives with my friends 69 Hemi RR.

64BEL · Jan 23, 2021

AR67GTX said:
My carbs have air bypass and mixture screws on both carbs - choke on rear only.

Both of the original carbs on my '66 are exactly like yours with 1 air bypass and 2 idle mixture screws each. Same numbers - 4139 and 4140. I think '66 was the only year for that setup.

Fran Blacker · Jan 23, 2021

64BEL said:
Both of the original carbs on my '66 are exactly like yours with 1 air bypass and 2 idle mixture screws each. Same numbers - 4139 and 4140. I think '66 was the only year for that setup.

67 Hemis had them also. Front carb in 67 was still 4139s and rear carb was 4343s. Had an extra arm on accelerator mount with a round rubber piece to cover a hole on driver side fuel bowl.

Ceedawg · Jan 24, 2021

The throttle blades are set closed in the bore, front and back carb. 67 fsm tells how to adjust properly. My 66 manual didn’t have anything about a Hemi. BTW I have a 66 Belvedere II 4 speed A1 silver black interior bench seat

AR67GTX · Jan 24, 2021

Ceedawg said:
The throttle blades are set closed in the bore, front and back carb. 67 fsm tells how to adjust properly. My 66 manual didn’t have anything about a Hemi. BTW I have a 66 Belvedere II 4 speed A1 silver black interior bench seat

thanks - I will check the 67 manual further as I have both. I was surprised when I looked in the 66 manual and there wasn’t a mention of the Hemi anywhere. I noticed in Classic’s catalog I believe - some sort of Hemi supplement for 66 but I’m not sure if it is an official Plymouth publication or not.

Dave6T4 · Jan 24, 2021

I had 2 X 4's on a 426 Street Wedge in my 1964 Polara 500. They were original carbs from a 1962 Chrysler 300H. They also used the large brass screw idle bypass system. Single 4 barrel on 273 Commando also used this.

Ceedawg · Jan 24, 2021

AR67GTX said:
thanks - I will check the 67 manual further as I have both. I was surprised when I looked in the 66 manual and there wasn’t a mention of the Hemi anywhere. I noticed in Classic’s catalog I believe - some sort of Hemi supplement for 66 but I’m not sure if it is an official Plymouth publication or not.

Chrysler added a supplement later on for the Hemi, there’s some copies out there for sale. From what I was told (from a guy who worked there then) no Hemi cars were built till early Dec of 65, not sure why, the book was before the 66 cars rolled off the line.

Dave6T4 · Jan 25, 2021

My best score ever at a swap meet was a pair of Hemi carbs. I was at local generic auto parts swap meet outside of London, Ontario about 20 years ago. A bunch of my Mopar buddies had gone to a Mopar meet at Norwalk, Ohio, but I decided to stay home, and went to this instead. I noticed that one vendor who had a lot of Chev stuff for sale had a pair of Carter's on a SBC 2X4 intake. Investigating further, I noticed the brass idle bleed screws, and I knew that Hemi carbs featured these. The guy wanted $150.00 for everything. I explained I did not need the intake, and talked him down to $80.00 for just the 2 carbs. 4139 and 4140 with the linkage. One of my friends that went to Norwalk that weekend had a 1966 Hemi Charger with the wrong carbs on it ended up with them. Obviously, the Chevvy guy did not know what he had!

Idle control on 66 Hemi

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