Throttle Fast Idle Cable Setup for Holley 3247
 

Has anyone had any luck fabricating/installing a fast idle hookup for the Holley 3247 for warmup. Stock coil choke works fine but the 3247 780 does not have the fast idle black box setup for the 66 427. It would be nice to be able to put about 1,000 rpm on the engine (426/425) for warmup for a few ,minutes instead of the awkward heel on brake toe on accelerator goat rope while backing down the driveway hill. Nope, parking brake doesn't work.

I guess a cheap wire cable could be rigged but maybe there are better ideas out there.

Thanks

is the problem your intake manifold cant accommodate a divorced choke coil to connect to the carburetor?

I have a divorced choke which mounts in a box on the manifold. Spring and lever to the choke which works well. But there is no provision for the fast idle function as in the black round thingy with an adjustable setting..They didn't see fit to have that setup on the 427/425, at least in 1965 or 1966. 67 3 deuce setup may have been different.

Tom the 3247 does have a fast idle cam in stock configuration. However, it does not have a set screw to set the fast idle like a lot of Holleys. Here is a picture of mine.

https://i125.photobucket.com/albums/...psryh06qbl.jpg

You may have to enlarge the photo to see it. It's in the middle behind the slotted link for the choke vacuum can pull off and where the rod from the thermostaic coil in the manifold hooks in. The cam is white plastic on the same middle stud with the "E" clip and behind the linkage - but you can see glimpses of the white plastic around it. The little metal linkage tab with the rectangular slot in the middle of it is the fast idle speed tang. It has to be bent to adjust where it rests on the cam steps to adjust the fast idle. The linkage from the choke plate pulls the cam around off of the tang to lower rpms as the choke comes off.

Great photo Dan, I guess I was unaware that a fast idle function existed in all of that plumbing..I'll get back with you tomorrow..

Thanks,

TC

Do you have the thermostatic coil and rod installed as in my picture?

Setting up a properly functioning choke action and fast idle function take a lot of trial and error. Must of us don't park these cars out in zero degree weather so they are usually started in 40 to 60 F temps in the winter and that may require some amount of adjusting things so that it doesn't over-richen or under-richen the mixture. In addition you want the choke to set enough to bring in the fast idle but you don't want it to be stuck on fast idle for a long period of time or for too short a period of time. Trial starts on a cold engine, watching the choke plate position and moving it by hand slightly to see if it needs to be set to close a bit more or open a bit more while monitoring the fast idle speed and hold is about the only way to get it to work well for your situation.

On a cold engine the coil should snap close the choke when the throttle is opened a bit. Then the vacuum choke break kicks in when the engine fires and opens the choke partly to allow air to pass so it doesn't choke out. Putting a vacuum gage on the can to hold it in the retracted position will allow you to bend the link between it and the choke linkage to adjust the choke hold open to Holley specs. Then when you test fire it, if it sound like it's loading up and running rich, adjust the link to open the choke a bit more until it clears up and runs cleanly on fast idle. Use a screwdriver in the slot on the fast idle tang to bend it to adjust the fast idle speed.

Wow, Dan. Yes, I do have the correct choke setup with the thermostatic housing and spring with the rod connected to the choke shaft with the E clip. Had no idea this carb had a fast idle cam. Think I'm going to have to have somebody who understands this system to help me get it set. I do appreciate all that info and I will get to work on it today. BTW the car runs great and as far as I can tell, not too rich, (no smoke) but I did check the mileage on my latest fill up and I'm getting just less than 10mpg. Wonder how that compares with yours.

Thanks a million...TC

The plastic shaft on the green cam can break and you will not have fast idle . The shaft holds the fast idle until heat up

It happened to me and puzzzled me until I looked at my spare carb linkages and saw the missing shaft. To see it you have to look behind as stated in other post. You can see it at bottom of picture

jack

ps...sometimes you have th bend the tab that grabs the plastic notches on the cam.

Jackfit may have a good tip on checking out the plastic cam - I have some other newer Holleys with the electric choke and they have a plastic pin I believe like he mentioned. But without getting my car down off the lift I can't recall if it has a similar pin as the linkage does work a bit differently.

Mileage - man, I probably go through a gallon just getting mine started and idling to where I can drive off. It has a pretty big cam and aluminum heads so it takes a bit to get enough heat built up in it to where it will run on curb idle although it will tick along on fast idle. Then with the L88 open plenum intake and slightly richened, staggered jetting for it, it's not a lean cruiser. And with the 4.11 rear and short drives around the neighborhood and nearby country roads I'm probably doing good to get 6 - 7 mpg.

This is the fast idle “adjustment” on a 3247 Holley. Do you have this tab? You bend it to adjust the choke idle.

https://cimg1.ibsrv.net/gimg/www.cor...482ced773.jpeg

you can also see the plastic cam in the picture above, it is not pure white

OK guys, here's what I've got. Looks like all the parts you mentioned are there. So, I'm not really sure what to "bend" to have a fast idle. The only thing I can move by hand is the choke butterfly. I can't really see what opens the primary bore butterflies for the fast idle.


https://cimg6.ibsrv.net/gimg/www.cor...6e393ac285.jpg
So, which of these components get "bent"
https://cimg7.ibsrv.net/gimg/www.cor...34802a12b0.jpg

The tab that is catching the notch on the plastic cam looks like it is catching. That should open throttle blades for fast idle. When engine heat come up , that tab will not catch the notch and allow the throttle to come back to low normal idle . Typicality, if you don’t have fast idle at cold start, it will not be in position because of choke spring moving cam into position but tab does not reach notch. That’s where the bending comes in. You have a simple fix, just need someone to check it out.

jack

j

OK guys, I've got it...twist the slotted tab slightly toward the front of the carb allowing it to catch on the nylon cam...Thanks

Read this by John Z.

http://camaros.org/pdf/tech_fast_idle.pdf