Carburetor Adjustment "Tip"

[2nighthawks]

I'm not usually one for offering "tips" on much of anything, and I can't take credit for this one as it's a handy little thing I learned from one of the other guys in our club, but I think it's a really good little thing to consider:

No two carburetors are the same, and even two seemingly identical carburetors can have very different "ideal" carburetor adjustments. It's a good thing to know the exact adjustment your Model T likes, especially the adjustment for a cold start,....here's why:

Recently, we had a very hard time getting one of the "T's that hadn't run for quite some time started, and almost, after quite a few failed attempts by several club members to get the car started,....almost gave it up for the day. Then, the owner remembered that there were a couple of grandkids playing in the car in the garage a few days before. All of the difficulty then became clear in that the kids had been playing with the choke knob and had obviously twisted it open and closed repeatedly, of course leaving it far from the proper adjustment for starting/running.

The "tip" I learned from this of course, is that it's good to "memorize" and, perhaps write down someplace, the exact number of turns from closed your Model T carb adjustment likes, in case some kid (or anybody for that matter) just can't resist playing with the choke rod/knob at a car show or something. Seems a small thing, but when the adjustment is way "off", especially when you don't know it,.....well,.....that simple little "situation" can cause real problems, or at least some "inconvenience" and or embarrassment,.....FWIW,.....harold

[Doug Keppler]

Harold that is not a choke knob, its a mixture adjustment, you don't turn a choke knob you pull it

[RustyFords]

I think he was referring to the mixture knob.

And you're right Harold...I've discovered since recently putting my T on the road, that it will simply refuse to start if the mixture knob is set a bit too lean. Richen it up though and it practically jumps to life.

[MrFixer]

That happens to me weekly.
My 1.5 year old and 3 year old love to play in the T. We often hop in for the evening cruise and I discover it will start after the choke, but it either stalls for a lean condition or it smokes and runs too rich.

One time during an evening cruise I was looking at some deer while driving and the engine suddenly felt under powered and then just died. I choked it and it would fire off but no matter what I tried it would not stay running. So I get out the cell phone and call the wife to bring a rope to tow me home. While waiting I look over at my 3 year old trying to turn the carb mixture adjustment clockwise but it will not move. Eureka!! He had been playing with it while driving the whole time I was looking away and turned it all the way closed. I quickly turned it back out to where it usually run it and it fired right up, then the wife shows up. Go figure.

So if you have kids or curious people playing, sitting or riding in you car, remember to check the mixture when the T isn't running right.
Just let them stay curious. getting mad, banning them from them playing or riding in the T will only quash their interest in you or in cars in general.

I have taught my 3 year old what the knob does and given him the job of pulling the choke and adjusting the mixture for the first start. Hopefully he stays interested and will continue the after dinner cruise.

[Ruxstel24]

When I was a boy, we were at a car event/tour and Pop was off somewhere. I was playing with the spark and throttle levers....when we left it was a short time before the old man said it wasn’t running right. Here the spark rod had came off at the distributor and it was still fully retarded. The exhaust manifold was glowing a nice reddish orange !!
Pop handled it pretty calmly.

[Norman Kling]

Depends on what year car you have! The later ones had the choke and the mixture on the same knob. So you could call it either the choke or the mixture control. The earlier ones had two separate controls.
Norm

[Altair]

My 26 has the choke and mixture using the same rod, pull for choke and turn for mixture. I experienced the same problem with children playing in the T and adjusting the mixture control. Mine started with one turn and ran with 7/8 turn, when I would stop it I would turn it one full turn open for the next start. This day it was at least two and a half turns open and I hadn't notice it until I was exhausted cranking then I thought I would double check. It always started with one or two pulls but this day no joy. After a readjustment back to one full turn it fired right up. I now always routine check the mixture control, it has become an automatic habit.

[hollanbl]

I am really new here, as I just purchased a 1922 Model T Runabout. I need a little more help regarding the carburetor adjusting rod. Mine has a separate carburetor adjusting rod and a separate choke. In the previous comments it was stated that the rod is turned but which way do I turn it. If turned to the left is the fuel leaner or richer. I tried for quite a while not knowing what I was doing but finally got it started. However, after I moved it I discovered that there was quite a bit of gas on the floor. I hope this is not the norm. Thanks in advance for any help/advice you can provide. Brad.

[Scott_Conger]

CCW is richer
CW is leaner (on standard NH and Kingston carbs typically found on a car of your date)

fuel on the floor may simply be a byproduct of trying to start it and over-choking it with bad adjustments.

Once it's running and has warmed up, lean it out until it stumbles and tries to die, and immediately but slowly, adjust rich until it runs well then further until it blubbers and smokes. You have now found "too lean" and "too rich" and the correct running setting is pretty much 1/2 way between the two. This is where it will typically want to run.

Now that you have that, to start, turn CCW 1/4 turn "rich" and also choke the carb while starting (hold choke for 2-3 compressions and no more). If it fails to start after a few moments, rechoke for 2-3 compressions and release again. Once running you will very soon be able to return the richness adjustment BACK the 1/4 turn to the normal running position and you should be good to go.

Welcome to the hobby!

[Quickm007]

Very well said Scott! Nice and clear explanation.

[RajoRacer]

Drop me a note if you need additional assistance - I'm just down the road in Longbranch. I heard you recently joined our local Kitsap Club.

[Scott_Conger]

Brad

Steve would be a great resource to you as you learn about your car. Take him up on his offer if only to meet and greet.

[JTT3]

Remember that running to lean can cause your exhaust manifold turn cherry red. The gas not only fuels the combustion chamber but helps regulate the internal cooling to a point. So don’t over do that, bad things can happen. Don’t ask how I know.

[Alan Long]

I have a notation on my Windscreen that reads 11 = 1. Ie when the notch on the mixture knob is at 11 o’clock
that represents 1 turn off closed on The carburettor. I leant this trick the hard way as did the first poster
Alan

[Original Smith]

Since I don't like to scribe a notch on my carburetor brass adj. knob, I've picked up several originals over the years at swap meets, where this has already been done. The original stays in the house with the goodies!

[hollanbl]

Wow! Thank you all for the help regarding carburetor adjustment. I will print this off and apply your tips the next time I start it. Hopefully, when the weather cooperates. I definitely would like to meet you all and learn much as I can. You have a wealth of information and experience that I know is invaluable. Thanks again! Brad Hollan