How to lean carburetor

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Model T Ford Forum: Forum 2014: How to lean carburetor
Top of pagePrevious messageNext messageBottom of page Link to this message  By Bruce Stafford on Sunday, January 05, 2014 - 10:39 am:

Ok al you experts (clearly I AM NOT ONE) I have a 26 Tudor that is 85% complete starting from frame up. I 've already fried the alternator but that is another thread. I'm trying to get the hang of throttle, spark, lean, etc. Herman Campbell did excellent job of rebuilding the engine but it is now installed and everything is hooked up. It's been roughly timed, thanks to other threads Now I want to start it and keep itrunning. Where in the hell should I have the lean? A reprint of the operators manual says turn it anticlockwiae then turn back until it runs well. Obviously there is all the way to the right (clockwise) or all the way to the left (counterclockwise). Where should that control be paced to start, that is should I start with it completely the left stop or right stop.. I've been on this old gal for 4 years and the worst part is having to get the body shop off their asses and get things done, Ugh! Thanks for all comments.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Sunday, January 05, 2014 - 10:44 am:

Crank it down slowly clockwise until it stops. DO NOT force it as you'll deform the needle. Turn it out 1 1/4 to 1 1/2 turns. this is the usual setting when starting from scratch. Adjustments are normally made after it warms up but you can fiddle with it a bit if it really runs badly.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Sunday, January 05, 2014 - 11:09 am:

Charlie has it for the first time you try to start the car after working on the carburetor. If you can get it to start, here is how I adjust it. Turn clockwise slowly until it begins to slow down, then go counter clockwise till it speeds up continue counter clockwise and it will begin to lope. Somewhere about halfway between slowing down and loping is where I run it. You might need to re-adjust when it warms up, or when climbing a hill. This re-adjust will only be a very little turn one way or the other.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Sunday, January 05, 2014 - 11:23 am:

Bruce
Assuming everything is working correctly, set the mixture control all the way clockwise (closed). Do not force it closed or you can damage the tapered needle. When the engine is cold open the mixture control counterclockwise about 1 and 1/4 turns. The throttle lever should be set 2-4 notches down on the quadrant. Starting on battery the spark lever should be set ALL THE WAY up. If the engine kicks back when hand cranking or starting STOP, the initial timing may not be set correctly. If this is the case contact me and I will help you set the initial timing. This is important as incorrectly set initial timing can be dangerous to the operator or starter or cause engine overheating.
Turn the switch to battery and try to start the engine while pulling up the choke rod for a second or two while the engine is turning. Go easy with the choke as it is easy to flood a Model T. Release the choke and the engine should start. Immediately advance the spark lever to about 1/2 way down.
As the engine slowly heats up you will notice the engine start to lope because the mixture needs to be leaned out. Turn the mixture control clockwise till the engine starts to run smoothly, you will find a sweet spot at about 3/4 to 1/4 turn open. All Model T's are a bit different so play with it to find your best spot for running after the engine is at normal operating temperature.
When the engine is at normal operating temperature you may not have to manipulate the mixture control when starting, but always set the spark lever up and the throttle lever down a few notches.
If this procedure does not work something is wrong. Get back with us with the indications you get and we can advise.
Good luck
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Sunday, January 05, 2014 - 11:31 am:

Ron's advice is perfect.

Here's another way to lean a Model T. I don't recommend it.



Top of pagePrevious messageNext messageBottom of page Link to this message  By Henry Petrino in Modesto, CA on Sunday, January 05, 2014 - 11:36 am:

Good advice above. Just one more comment - I've found that once I have the mixture adjusted to the "sweet spot" when it's warm further adjustments when cold do not help. Now that I have it properly adjusted I never monkey with it. I just use the spark and throttle levers and the choke when starting it, cold or hot.

I know others make adjustments regularly. I'm just sharing my experience. Your mileage may vary.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Sunday, January 05, 2014 - 11:59 am:

No hills or hard pulls in my area so I agree with Henry. Never could get it any sweeter by monkeying around after it's set.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ross Benedict - Calgary, Alberta on Sunday, January 05, 2014 - 12:15 pm:

Steve, been there, done that. Strange how those puppies just jump forward on ya, eh? !!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Sunday, January 05, 2014 - 12:31 pm:

Once the engine is started and adjusted to run well some reasons to change the mixture adjustment include:

1. Many people find that turning the the mixture open/richer (CCW) 1/4 to 1/2 turn will make it start easier.

2. If the engine is running too hot (the exhaust may glow red in low light), then it may be too lean.

3. When making large changes in elevation the air is much thinner and mixture may need to be adjusted. Adjust leaner when increasing elevation and richer when decreasing elevation.

4. If the spark plugs are black and sooty, you may be running too rich.

5. If you have a problem with carburetor icing, running a little richer may help.

6. Many drivers report a little better power on a hard up hill pull with a little richer mix.

7. If you run E85 fuel (E85 is a high-level gasoline-ethanol blend containing 51% to 83% ethanol), the adjustment would need to be richer.

8. If you are getting really crappy fuel mileage, you may be running too rich.

Anyone have any other reasons to adjust the mixture?

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Sunday, January 05, 2014 - 12:55 pm:

I thought of one more.

Once the engine is started and adjusted to run well some reasons to change the mixture adjustment include:

1. Many people find that turning the the mixture open/richer (CCW) 1/4 to 1/2 turn will make it start easier.

2. If the engine is running too hot (the exhaust may glow red in low light), then it may be too lean.

3. When making large changes in elevation the air is much thinner and mixture may need to be adjusted. Adjust leaner when increasing elevation and richer when decreasing elevation.

4. If the spark plugs are black and sooty, you may be running too rich.

5. If you have a problem with carburetor icing, running a little richer may help.

6. Many drivers report a little better power on a hard up hill pull with a little richer mix.

7. If you run E85 fuel (E85 is a high-level gasoline-ethanol blend containing 51% to 83% ethanol), the adjustment would need to be richer.

8. If you are getting really crappy fuel mileage, you may be running too rich.

9. If you flood the engine the mixture adjustment can be used to quickly clear the flooded condition. To clear the flood, gently and fully close (CW) the mixture adjustment, then crank the engine till it tries to start, reset the adjustment to normal and start the engine. Model T's don't take much choking and will flood easily.

Anyone have any other reasons to adjust the mixture?

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Clayton Swanson on Sunday, January 05, 2014 - 04:03 pm:

those darn trailers are nothin but trouble


Top of pagePrevious messageNext messageBottom of page Link to this message  By Warren W. Mortensen on Tuesday, January 07, 2014 - 12:17 am:

A lot will depend on the type of carburetor also. I've got a Holley G on my '17 that starts easier opened a 1/4 turn richer. Once the engine starts it's the first thing I adjust after fiddling with the spark & gas. If I leave it more than 30 - 45 seconds, the engine starts to load up. The Holley NH on my '26 on the other hand stays where it is as Henry described.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Harold Schwendeman - Sumner,WA on Tuesday, January 07, 2014 - 02:21 pm:

Jim - I've found that a sure way to deal with a "flooded" condition is to switch the ignition "off" and crank the engine through several strokes with the throttle wide open to pull lots of air through the engine, as it's the cylinders as well as intake system that have too much fuel mixture and raw gasoline in them. After the above, invariably, if everything is in good condition, with throttle open a couple notches and spark retarded, the engine will invariably start right up without any additional choking.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bud Holzschuh - Panama City, FL on Tuesday, January 07, 2014 - 05:03 pm:

Like Warren I find mine starts better about 1/8 turn richer than normal running position . When its hot but has been sitting 30 min or so, it won't start unless I turn the mixture 1/8 leaner than normal running position. YMMV


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Tuesday, January 07, 2014 - 07:55 pm:

I'm one who richens 1/4-1/2 turn on a cold engine (Summer and Winter respectively). What really amazes me, though, is how fast the T engine "Warms up" and wants to be leaned out. It is usually less than a minute. Sometimes about as long as it takes to put the crank handle back in its sling and walk around to get in. I don't believe it is really "Warming up" that quick. Heck, you could probably still touch the exhaust manifold at that point without serious burns. Anybody care to speculate on what's going on? But don't tell me I didn't need to richen it. I've tried it with and without. Without richening, it will burn the priming charge out and die, over and over. But if I richen beforehand, just one pull with choke and it starts the next pull.....on mag, I might add.:-) But then it lopes after about 30 seconds until you lean it back out.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Daron - Brownsburg IN on Tuesday, January 07, 2014 - 08:31 pm:

Hal,check the tip of your needle.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Tuesday, January 07, 2014 - 09:10 pm:

Jack,

I will certainly do that, but I'm curious as to what is your theory?

BTW, my TT and my wife's Touring both exhibit this behavior. Both have Holley NH's. I was thinking this was perfectly normal.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Daron - Brownsburg IN on Tuesday, January 07, 2014 - 09:18 pm:

I run NH carbs,once set,never touch them.Check needle.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Wednesday, January 08, 2014 - 07:46 am:

I understand, but what do you think I will find? Rounded tip? Groove around the taper? Something else? You must have a theory. Just interested. That's all.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Wrenn on Wednesday, January 08, 2014 - 09:40 am:

Steve and Ross...add me to the "lean-in club"!! That's exactly how I loaded my first Model T for the very first time as the then former owner looked on in awe (or maybe something worse). I'm doing much better now!!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Wednesday, January 08, 2014 - 09:47 am:

Steve Jelf shows an easy way to fix a grooved spray needle here: http://www.youtube.com/watch?v=uTiStUTU9IE


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Menzies on Thursday, January 09, 2014 - 10:52 am:

The carb manual I have says 7/8 turn to start and immediately after it starts open to 1 turn. I have found this quite specific if I try to start with 1 full turn it is a no go, it always start at 7/8 turn. Maby different models of carbs have different settings? Check your model for starting procedures.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Thursday, January 09, 2014 - 12:52 pm:

David,
What kind of carb is your manual for? That is really contrary to most folks experience, can you post a photo of that page?
Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Thursday, January 09, 2014 - 01:27 pm:

Always interesting to me when someone asks a basic question, requiring a simple answer, and 4 days later the original poster has disappeared and folks are still replying.

I'm not picking on anyone, it's just interesting to watch how a "conversation" flows on the forum. Just an observation.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Thursday, January 09, 2014 - 02:38 pm:

Jerry,
I think your observation is right on. Maybe sometimes folks just ask something like "what kind of oil should I use?" just to sit back and watch the reaction. Many times people can find many ideas by looking at old threads. However in this case there really in not a lot out there on what and when the mixture should be adjusted.
Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Thursday, January 09, 2014 - 04:04 pm:

It's no different than a verbal conversation. They evolve. Nothing wrong with that. I'd like to think that Bruce got his question answered. Well, at least got enough information to make an intelligent decision, as the real answer is "It depends."

But just because the question was answered doesn't mean someone shouldn't be able to continue discussing related ideas that come to mind because of the original discussion.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem on Thursday, January 09, 2014 - 10:56 pm:

Hal,

Again, "I'm not picking on anyone, it's just interesting to watch how a "conversation" flows on the forum. Just an observation."


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Daron - Brownsburg IN on Thursday, January 09, 2014 - 11:26 pm:

It would be nice to hear a response from some. At least you'd know if your hunch was right or not.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Friday, January 10, 2014 - 07:34 am:

Jack,

I promise you I will check my needle. Just haven't had a chance. I will do it and post my results.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Friday, January 10, 2014 - 08:39 am:

As an add on, the condition of the needle is a significant difference maker, obviously. I also will put out there that the length of the needle taper significantly affects how wide the "sweet spot" is. What I mean by that is this.....if the needle is resurfaced with a relatively short taper, the relative "openness" of the fuel seat happens in less turns (result...narrow sweet spot). Longer needle taper = more turning to get same relative openness (relatively wider sweet spot). I like to surface the needles on my NH carbs to a longer taper than stock as it results in a greater relative adjust-ability for "sweet spot" fine tuning. I hope that made sense.


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