How is the choke Rich/Lean mixture properly set? I know how to adjust it, I need to know how rich or lean to make it. 360 / 4speed W/ A 680 vac secondary quickfuel technologies carb

Hello? Anybody out there ?

You tune it to your particular motor.

How do I tune it to my motor? Enrichen it till it chugs then back it off a bit? I have the choke idle set to raise the RPM's a few hundred yet still need to know how rich it should be.

The instructions that came with the carb did mentioned that the further the enrichment is turned the longer the choke will stay on. That is about all it said for choke adjustment. It seems the farther I adjust it towards rich the farther the choke door closes. Would that not make it have a richer condition seeing as it is limiting the air going into the carb? It does have a choke idle also that I have adjusted to raise the RPM's a few hundred over no choke.

What kind of choke are you using? Electric choke or are you using an original choke set up?

""It seems the farther I adjust it towards rich the farther the choke door closes.""

Exactly! The more the door closes, it allows less air which is why it gets richer.
Try testing it for your car. Each time you start up the car, try moving it two marks richer and see how it starts. Keep notes on how it starts and then when you are done readjust it for what worked best. As it gets colder outside, adjust it richer.

Thanks for help from the "Northern Bro's" I'll tune for my climate and adjust for seasonal change. I was dialing it in this evening and it seems to be working better now. Burn rubber!

A general baseline would be to adj it to where it lightly closes the choke at 70 degrees F & then fine tune it from there.

Aftermarket electric chokes, run as-is, are a compromise at best. You set the choke where the engine starts and runs well, and the darn thing is wide open in about 1 minute. You set the choke rich enough that it stays closed for a decent amount of time, and the engine runs so rich at first that you've killed the spark plugs.

I'm speaking of the Holley electric chokes, and I'm assuming yours is similar.

The electric choke has no idea how hot or cold your engine is. You put 12 volts on it and it opens. If the ambient air is colder, it'll open a little slower, but still...

Here's what I did, and it works fairly well. First, set the choke to the point the engine starts and runs well, no chugging, no spitting back. Don't worry about the fact that the choke will open too soon. Find the happy spot where the engine is happy when first started, leave it there, then set the fast idle to match it.

Next, you're gonna have to slow the opening of the choke, if yours is anything like the Holley units I've worked with. I added a 20 watt power resistor (availabe at any decent electronics store) in series with the choke heater to slow the opening of the choke. I think I have a 27 ohm resistor in mine now, and my choke heater is around 10 ohms IIRC. I actually experimented with with various resistors on the bench and timed the choke opening and recorded it in my notebook, which is at my shop now and not at home. I'll be happy to post the data later if anyone wants it. You play with different resistor values to tailor the choke opening time to what your engine is happy with. Lower resistance = faster choke opening. Higher resistance = slower choke opening.

OK, so we've set the choke where the engine starts and runs well, and we've slowed the choke opening with a resistor. Only one problem left to address. You turn the engine off, and the choke closes before the engine cools off, b/c the choke is divorced from the engine. You then start the engine and it runs rich for a long time b/c we added a darn resistor to slow the choke opening!

If your engine has any provisions for the hot air tube, you obviously should connect that to your choke. Mine didn't, so...

You add a thermostatic switch something like this

http://cgi.ebay.com/12-Temperature-N-O-C...id=p3286.c0.m14

and put your resistor in parallel with it. This way, when the engine is cold, the switch is open, and power flows through your new resistor. When the engine is hot, the switch closes, the resistor is bypassed, and full voltage is applied to the choke, allowing it to open fast. Chrysler used a similar switch and resistor setup on some of their electric chokes in the 70's. It looked like this

http://cgi.ebay.com/ebaymotors/NOS-Mopar...emZ150291925912

If you decide to use one of the cheapie eBay-type themperature switches, you can mount it on a piece of sheetmetal and screw it down under an intake manifold bolt like the factory did with the above unit.

I know this sounds like a lot of work just to get the choke to function well, but believe me, I've been through it and if I could have found an easier way to make mine work well, I'd have done it. I used a wideband O2 meter to lean out the very rich part-throttle cruise condition that all Holleys seem to plagued with then, as expected, the engine became very cold natured, making proper choke operation quite important. I was forced to make my choke work.

DISCLAIMER: The above solution worked for me. Your mileage may vary.

Good luck.

Jim

I just opened mine completely for summer use and in winter here in DC I set it where it the door just closes, which on mine was one click rich. I think the Edelbrock manual says to start 2 clicks rich. One works well for my 44o, but depends on temp of your climate. Just mess w/ it. My biggest issue is remembering what I did w/ my torx bits!

JimG you've done your homework

Nice high tech solution JimG!!

I have a low tech solution if that carb is still too rich but you want to turn the choke to lengthen the duration. I am going to assume that your QF carb has apx 70-71 iab's which works well for the in gear idle rpms but they may make the cold start a tad too rich if you turn the choke to the richer settings which closes the door almost completely. I found with my QF unit that I wanted a longer duration choke timing but I wanted to open up the choke door for a leaner startup, so I tried/tested a cheap fix.
If you look at the red arm attached to the back of the electric choke, you will see that the higher upwards it goes the more closed the choke plate gets. So I took some electrical tape and cut it in half length wise. Then I made a spacer donut on the choke mounting leg (as shown in the picture) by just adding more tape around the leg and then tested the choke plate opening with the choke set. When you look at the picture you will notice how far open the choke plate sets with this donut spacer. I have found that this is an easy way to lean/richen the choke plate setting while keeping my choke duration setting longer. This donut is hidded once the air cleaner assembly is in place and it is easy to adjust with either added another piece or removed a piece of tape. You will need to readjust your high idle rpm.

OK, after reading that twice and looking at the pic, I see it now.

Basically, you're stopping the choke mechanism from moving past approximately halfway. You can crank the choke spring 'til the cows come home, and the choke will still only open about halfway.
The only potenial problem I see with it is this: do you get any vacuum pulloff when the throttle is opened, or does the choke blade stay fixed in that halfway position?

Nice Yankee ingenuity there no matter what!

Jim

Jim,
The choke plate goes full vertical like normal once the engine is warm enough.
All I am doing is limiting the closing point of the choke plate as the red lever just comes up and rests against the donut which keeps the choke plate from fully closing. I can set it as shown for the warmer temps and just pull off a few pieces of tape to allow it to close farther for the cooler temps. My setup does not like the choke plate to be fully closed even in cooler temps (50's in my case) so I came up with this method.