Electric Choke Frustrations

[Orion88]

I rebuild an Edelbrock Performer carburetor and installed it, along with a Performer EPS intake, onto the 350 of my 86 K10. Since it's the dead of winter here in Indiana I need the electric choke to be working properly and so far, it's not. I initially set it to where the choke was just barely closed when cold. When I would fire it up it would run perfect for about 5 seconds. Then it would start burbling and gurgling and sometimes it would flood itself out and die. If it didn't die it would eventually run properly at fast idle after a minute or so of almost flooding out. I tried rotating the cap while putting some pressure on the throttle but the choke won't move. Earlier when I would adjust it the choke would move in whichever direction I rotated the cap. Now it won't. So starting my truck when cold is a real chore right now. What's the deal with my choke?? I took the cap off this morning and everything looked ok so I put it back on and it still isn't working properly. Anyone ever have these issues?

Also, if your form of helping me out here is to tell me to throw the electric choke away and put on a manual choke, that's not helping. I spent the money on the electric choke so I am going to make it work right. I've read far too many positive reviews on this product to accept defeat. And I hated the last manual choke I had even more.

[K5owner]

First are you sure you rebuilt it correctly? The chokes on these carbs never work especially well in really cold temps. To be honest the carter and edelbrock carbs are what they are. IMHO they are nice for a warm weather street rod but not our trucks especially anything off camber or off road. You would be better served buying a rebuilt quadrajet from SMI. https://www.smicarburetor.com/produc...ID2/86/sfID3/9
For as much as people fiddle with the edelbrocks and still complain about poor mileage and hard starting you would be money ahead by getting a quality rebuilt quad and running that or upgrading to fuel injection for cold weather reliability. Sorry to not have a better answer. I like edelbrock carbs just not for these trucks.

[Orion88]

Yeah, this is the third Edelbrock I've screwed with and they are all temperamental when it gets cold. I rebuilt it just fine. Once the engine is warm it operates just as it should. It does like to cough coming off idle if I try to accelerate too much before she is up to temperature. Not sure what the deal is there

[K5owner]

Unfortunately your experience with these carbs mirrors mine. Sorry I don't have a better answer for you.

[rich weyand]

Well, I have a five-year-old Edelbrock 1406 on mine, and last Thursday I came out to the truck at midnight, at 2* below, where it had been sitting parked outside in the open for five hours. I pushed the throttle to the floor once, released, and turned the key. The crank didn't make one full revolution before she caught and ran fine on high idle.

We're only a couple miles apart. Why don't you come over here and we can park them side by side and do contrast-and-compare and see how your setup is different than mine. Those little cams and widgets on the choke and throttle connections can be difficult to get set up correctly. One little cam out of place and she'll never run correctly.

[tucsonjwt]

I hope your electric choke works for you and Rich can get it set correctly. I personally have never had any luck with "automatic" chokes of any kind -either in the sub-zero Michigan temperatures or in the desert southwest. So, I have always installed a $12 manual choke.

You know for sure when the choke is open or closed, and you can control how much the choke valve is open - sometimes you want little or no choke in cold weather after the vehicle is started Example: you are stopped at an intersection on an icy or snow packed road with the temperature at 10 degrees below zero. Your automatic choke still calls for full choke application because of the cold temperature. This causes the engine rpm to increase to a high idle. You attempt to pull away from the intersection but your rear tires spin on the ice and you cannot get traction. If you have an manual choke you can open the choke partially or completely until you get underway. In fact, you can usually open the choke partially or completely in cold weather once the vehicle is somewhat warmed up.

[bnoon]

To set the electric choke initial setting, you have to NOT engage the fast idle cam. If it is engaged, slightly open the throttle by hand and move the fast idle cam away from the throttle linkage to get it OFF of fast idle. Then you should be able to move the plastic choke and set the initial choke flap starting point. Once that is set, don't mess with it. It should be just barely closed to maybe open 1/32" at most.

After that, you adjust fast idle screw and that is it. If it doesn't work, you've messed something up during the rebuild.

[rich weyand]

He came over and we took a look at it. A couple of things:

1) the idle mixture was set right.

2) the accelerator pump squirt was in the least position, and should be in at least the middle position.

3) the timing is likely not advanced enough. He thinks it's around 4* BTDC, but I couldn't see the marks. Timing wheel needs to be cleaned up so the marks are visible and base timing set to at least 12* BTDC.

4) throttle return spring is inadequate, and does not return throttle all the way unless you get on it and then release so it snaps back. It may not be tight enough to hold the high idle screw against the high-idle cam until it warms up.

5) choke was set on minimum because he was convinced it was flooding. Not sure about that. Sounds more like lean sag to me.

6) It's the big Edelbrock, 750 cfm, which is a lot of carb for a 350. Stock tune. And no idea what the A/FR is running at.

So some things to clean up. Trying the 600 cfm on there, which he has one of, would be a good idea. Then he could try my tune for the 1406: Primaries: jets .092 (#1425), rods .062 x .052 (#1441); secondaries: stock; step-up springs: 8# (comes with #1464). Also need to replace the airhorn gasket (qty 5 is #1499) and adjust the float bowls while it's opened up.

[piecesparts]

Agree with the comment about the 750 CFM carb on a 350 stock engine. Way too much. As for setting the electric choke. Take the air cleaner off, with the engine cold--NOT recently running, and loosen the choke module holding screws. Next move the choke back and forth until you see the choke plate start to move in the closed direction. This should be a good starting spot for the choke adjustment. If you need more choke setting from that point, do it in small increments.

I also agree with the information given above about tuning the carb. It can be done for the 750, but I think that is still too much for a street driven engine. If you were using this to drag race or pull with, then the 750 would start to fit in, better. If you were to talk to any of the carb manufacturer techs, they would tell you that the CFM is not the important thing, but the air flow through the carb is more important. For a heavier vehicle, like a truck, the air signal given with a 600 to 650 carb would be better for daily use, than a 750 carb. Now if your vehicle was a light weight Camaro, then the 750 would fit the bill much better.

Many persons do not like the Edelbrock and Carter AFB design carbs, due to the mechanical secondary's, but they can be adjusted to work quite well, if you spend some time with them. I am running a 650 Edelbrock AVS carb on my 383 stroker and it works great for me. I just set it up with a chart that I made to figure the size of rods as compared to jet size and I worked with it until it got to an optimum point.

[Orion88]

Yeah, I knew the 750 wasn't ideal from the start but I had never rebuilt a carburetor and I needed something to take my mind off grad school for a weekend. My 79 is parked for the winter and I think I am selling it in the spring so I will probably snag the 600 off it and swap the choke over. I just have to have both trucks in the same place at the same time.

[rich weyand]

Another idea is to take another look for vacuum leaks. I didn't see any, but....

[Orion88]

She is warming up right now. I fired it up and then I had to open the choke by hand to keep it running right. It's like it needs the choke upon fireup, but 5 seconds later it starts flooding and I have to hold the choke open for it to idle smooth.

[rich weyand]

You said your gas mileage was awful, too, right? That means the cruise circuit is too rich. If the high idle puts you into the cruise circuit, and it's way rich, that might do it.

The simplest thing to do is put a bung in the driver's side exhaust pipe right after the flange, and put my A/FR meter on it. Then we could at least see what we had.

[Orion88]

I should probably switch carbs first then go from there. Maybe I will have time to do that this weekend if I'm lucky.

[rich weyand]

My A/FR meter uses an 18M bung. The number 2 and 3 items on this page are the right size. Tom Cherry will weld it in for 20-30 bucks.
http://www.jegs.com/p/Allstar-Perfor...49541/10002/-1

[rich weyand]

Thinking about it, the carb tune for the two engines should be real close. If you decide to put the bung in, do that first, we can tune the 750 where it's at, then swap the two carbs and we can tune the 600.

Saves putting a bung in the other truck, and gets it in better tune for sale.

[bnoon]

It almost sounds like you're pulling fuel from the main feeds at idle once it's started instead of just from the idle circuit. Do the Edlebrock carbs have adjustable/replaceable air bleeds? Something is off, even before you get to actually tuning the rest of the carb for performance/cruise circuits. How are the float levels???

[GRADYS Performance]

Put a hot air tube from the choke to the exhaust manifold. A part number 3665 Mr Gasket choke stove kit will work on most Holley and Edelbrock electric choke carbs for cold weather use.

[Orion88]

bnoon, I set the float levels to spec. I don't remember the measurements but I used Edelbrock's suggested settings.

And I agree. it does seem like I'm pulling from the main feeds. I had to hold the choke FULLY open to get it to idle smooth. Something isn't right and I don't know what. I reassembled the carburetor how it was supposed to be, followed the instructions, took tons of pictures before and during disassembly, didn't have any spare parts, so I have no idea what to think now.

[cerial]

-Check to see if you have power going to the choke.
-Use a vacuum pump with integrated gauge and test the choke pull. Most people rebuild the carburetor and never replace the vacuum canisters wondering why the carb is junk when the canisters was the problem from the start.

As a quick test. If you are able to throttle the carb up the vacuum canister should open the choke. If not the canister may be weak.

-Replace all your vacuum lines. It is a cheap way to eliminate a large amount of guesswork.

Edelbrock, Holley, and Carter are all great carb's if used and tuned correctly. I have never had any luck with Weber. But most guys swear by them. It is all personal preference. I prefer Edelbrock because you can find them cheap and they take a lot more abuse then others.

I have crates of 2/4 jet and center drop of various cfm Edelbrock's from over the years. I have a few Holley's in there with many TBI for stealing parts off of. That being said some times the newer stuff is better(Holley). For $400 or less you can get a shiny new/newish carb. While that is a lot once you replace all the worn parts on a $40 junk yard carb you are going to be around $200 invested.

I ran a 650 avs this winter on a 350 in negative temps starting it around midnight over and over. I have the msd box on a switch and cranking the engine 10 or so times then flipping the switch allows for better starts.

Otherwise it does that thing where the engine starts then dies then needs to be started again or runs around 600rpm until the oil pressure builds.

Cranking the engine 7-10 times then waiting 10 or so seconds once the coil/choke are on gives a better start on carbs ranging from 300 to 850cfm on various engines over the years. Most of the time the vehicle fires on the first crank once the coil is powered and the idle evens out quickly. The hot air intake and pcv systems make a big difference in easier cold weather starts. If they are removed or not working you will have bad starts. I run different intakes during the winter then during the summer when I can get away running my cold air setup.

It sounds like your running rich and need to lean out the carb. Many things could have caused a over rich condition during the rebuild. Bent rods/tips comes to mind.
A 750 is way to big to start with. I ran my last modified 350 with the 650avs to 6600 so many times I needed to turn the limiter up. I never hit a wall fuel wise.
I would chuck/sell the 750 and start working on a 650. I got my AVS for $350 in box. Because I did not want to wait on shipping.