Manual choke or Electric choke?
 

I have a electric choke on my old 4160 600 cfm Holley carburetor and after a very long struggle trying to set it right I'm considering going manual choke so that I can have total control of when it's on and when it's off. I'm curious what my fellow enthusiast think about my decision? I appreciate any and all feed back from anyone that has a manual choke.

Well, I've been fortunate. I have an electric choke on my original 4350 and it does a fairly good job. It was about 30 degrees today and she started right up and warmed up nicely. But my buddy back years ago had a manual choke on his 390 and he loved it. Most folks that I talk to that have manual chokes seem to like them, for the control that they provide. I don't think you could go wrong and they seem simple enough to install. Good luck!

They both work fine. But the chokes need to be set up correctly and with age that involves replacing hard parts to get the choke to work. These days I don't even bother with old carbs and just replace with new. They don't last forever and new carbs sure are nice to tune.

I will never have another electric choke. Manual chokes give you full control of warm up. But most importantly, you don't have to worry about an E choke getting out of adjustment and partially closing the plate after warm up. I've chased that issue before. It's hard to diagnose because.

I replaced my electric choke Holley carb with a manual choke version. I like it much better now.

The problem with aftermarket or fully electric chokes is that they work off a timer. As such, they are not very accurate. Sometimes they come off too soon, and sometimes they choke the engine when it isn't even needed. The only advantage is that they are cheaper and the easiest to set up - just hook up one wire.

A manual choke works good as long as you know how to use it correctly. But the problem with a manual choke it that the user is estimating how much choke to give, when to give it less and finally when to bring it off. In other words, they are also not very accurate. But, they are cool and work very well once you get the hang of it. The disadvantage is that it is the most involved to set up and use; you have to route the choke cable from the engine bay, through the firewall, and bolt it into the cab.

The Ford thermostatic "hot air" choke works better than the other two for a few reasons. Unlike fully electric and manual chokes, a thermostatic choke automatically opens and closes in lockstep with the actual engine temperature. And since it will only choke the engine as much as it needs, it is much more accurate. This results in better, smoother drivability, cleaner emissions, better fuel mileage, and longer engine life. The disadvantage is that it is not as easy to set up as a fully electric choke; you have to hook up two air tubes in order to make a heat riser to the choke cap.


Given the choice, I would choose the thermostatic "hot" choke first (that is what I am currently using), a manual choke choke second, and a fully electric choke last.

I have a manual choke and like the control it gives me.

The one thing I DONT like about it, is it's not "smooth". I have an Edelbrock 1405. If you look at the choke idle cam, it basically just butts up against a screw when the choke is on, and holds the throttle plate open. The problem is, there's a lot of friction there. So if you try to push the choke to re-open it, it resists quite a bit because it's being held in place by the end of the stupid idle speed screw "scraping" on the cam. So you have to push in the throttle pedal and THEN push the choke in. As you can expect this doesn't really give you much "fine" control especially if you want to take the choke off while at a stoplight you pretty much can't. And even then it still fights me quite often. I have a new choke cable, too. They like to get bound up easily IMO. That reminds me I should go out and relube the cable again with some lithium grease spray

A manual choke with a cable , so far for me, is just not butter smooth, it's a fight because the cables always start to bind.

I have been thinking about making a "manual -electric" choke, where I would mount a servo motor to the choke arm to move it, and then run wires into the cab with an Arduino that controls the servo, with a potentiometer (knob) so I can just turn the knob to adjust the choke. Because it would be using a servo, it would be strong enough to overcome the idle screw friction, and it would also give me excellent accuracy, I could control it exactly with the knob. BUT that means one more electric thing always running that could fail, too. I'm also concerned about the servo withstanding under hood temperatures, at least if I tried to use a cheap hobby servo, it may not like it.

I wish they would have put a small wheel on the end of the idle screw so it would let the cam easily rotate.

Its not difficult to figure out how to operate a manual choke. But if you have trouble, one of the benefits of installing an AFR gauge is that you can adjust your choke during warmup by watching the gauge. I adjust to keep the gauge between 12.5 - 13.5 during warm up. Air fuel ratio will steadily get richer as the intake temp rises, so adjust choke as needed until it's warmed up enough to drive.

Interesting. Thanks for explaining that.

Except, why do you have to wait until "it's warmed up enough to drive?" Do you not have a fast idle cam?

My truck has a thermostatic "hot air" choke, and I can drive away immediately if I like without any sort of problem. In fact, other than depressing the throttle once to set the choke before starting a cold engine, there is very little difference in cold starts and cold weather driveability between my truck and a modern vehicle with EFI. :)

So those of you with electric chokes, when you set your choke by pressing gas pedal to the floor is your choke plate flush against the top of the carb. or do most have a small gap at initial set up? I have a quarter inch initial gap and it still takes a very long time for my choke to go completely off. If I open my choke plate even further am I not going to loose the effectiveness of the choke all together? Thanks for all the responses so far.

i dont wait to drive either, choke has a fast idle cam, hits around 1000 rpm in drive, i can start driving immediately and about a mile down the road time to open the choke

I hear you. I used to do the same thing. But heat risers and electric chokes don't know what the manifold air temp is, if the carburetor is tuned correctly, or what air fuel ratio is at varying temps. Ignorance was bliss before AFR gauges became affordable and easy to install. But now I've got AFR and vacuum gauges in all my carb vehicles, and can see what happens when I load the engine before it's warmed up on cold days. Lean spikes damage engines fast. But I can control the air fuel ratio during warmup with a manual choke. Yes, I could drive away immediately upon setting the choke. But I prefer to just be safe.

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Yes, when you press the gas to set the choke on a cold engine, the choke plate should be completely closed. There should be a little tension holding it closed, more if it is colder. When the engine first starts, the choke pulloff should immediately crack open the choke plate slightly. As the engine warms up, the choke should gradually open all the way.


I hear you. Although not completely necessary, I typically let my vehicles drop down off the first notch of the fast idle cam before I drive away. But this usually only takes a few seconds or so.

Most people don't realize this, but the cold fast idle speed should be set to 1600 RPM when the engine is at full operating temperature. When set correctly, the fast idle speed will be close to that when the engine is cold and the outside temperatures are mild to warm. If the fast idle speed is close to 1600 RPM, that tells you the choke is ready to come off. Depress the gas pedal, and the fast idle cam should drop down. If it comes down one notch, engine RPM will drop to 1100 RPM, which means the engine still needs a little choke. I will typically drive away at this point and let it come off the rest of the way automatically as I drive the vehicle. If it drops all the way down to curb idle speed, that means the engine doesn't really need the choke at all.

If outside temperatures are colder, the fast idle speed may only go up to 1100 RPM or so initially. When that happens, I typically let it warm up a little until the engine RPM begins to rise to about 1600 RPM. Then, I depress the gas pedal and the fast idle cam drops to the second notch. Engine speed will drop down to about 1100 RPM. Again, I will typically drive away at this point and let it come off the rest of the way automatically as I drive the vehicle. It is actually better for your engine to drive away sooner, rather than let it sit and "warm up" or idle for a long time. Your vehicle will come up to full operating temperature faster in one mile of driving than if you let it sit at idle for 10 minutes.

The stock thermostatic air cleaner will also help the vehicle to warm up faster and provide better driveability in all weather conditiions. Carbureted engines and even throttle-body fuel injection systems need a hot air source for better fuel atomization in colder conditions and to prevent carburetor icing. It is a true "cold air" intake as well, so it will also help when the weather is hot. By keeping the incoming air going into the carburetor at a somewhat consistent temperature, seasonal carburetor adjustments are often no longer needed. :)

Yep, ignorance is bliss

If you are experiencing "lean spikes," then something isn't set right on your carburetor or you are not operating your manual choke correctly, Chief.

The whole purpose of a choke is to enrich the air/fuel ratio to prevent that from happening.