Need proper air and gas mixture for H

Just had the carb rebuilt. Need to know how to set the air and gas mixture

Start with the idle mix at 1.5 turns out, and the load screw about 4 turns. When warmed up, adjust the idle speed to a slow idle (SLOWER IS BETTER) then adjust the richness to best speed and sound. Readjust the idle speed for slow, and readjust the mixture. 3 times should get to best idle. From idle, pull the throttle open quickly you should see a small darkening of the exhaust then clean clear exhaust. If it smokes darkish black and stays there, turn in the load screw 1/2 turn and try again. continue till it just shows a little dark and cleans up. If it stumbles ans misses, open the load screw till it acts like above. When plowing or using it under 3/4 to full load at high load speed, adjust the load screw out maybe 1/2 turn. If puttsing around at low load, it can be turned in maybe 1/4 turn. Jim

You will want a ratio of 14.7 air to fuel mixture under no load, drop it down to about 11:1 under load.

The stoichiometric mixture of 14.7 to 1 is the mixture where any richer causes hydrocarbons and carbon monoxide to go up and any leaner causes nitrous oxides to rise. The mixture is for emission standards on cars and trucks with catalytic convertors. The mixture is for minimal emissions and not for best running. The Farmall H would be lean at this mixture and idle poorly.

Im assuming, as no one told me, that the idle screw is the one at the lower L of the carb facing it, and the load screw is the other one. Am I right about that?
IF SO
Then what I get that your saying is, turn the lower L side screw 1 1/2 times out to start, and the upper screw at 4 turns. Is that right.
Does adjusting the lower L screw slow down the tractor? Then I see where you say ( 3 times (TURNS)? should get to best idle)????
Then you say turn in the upper screw if when opening up the throttle it stumbles or/and smokes, and turn it out if it stumbles. Am I right or wrong about this?

Idle adjustment is the one up close to where it bolts to the manifold. in for richer out for leaner. But 1.5 turns out and leave it is pretty much it.
The one that sits lower is the main jet adjustment and you set it around 4 turns out then fire it up and adjust to what makes it run the best under a load

Thanks ALOT for the info.

Here's my carb adjustment procedure for my 1950 "H";

Make sure the float isn?t sticking or touching the insides of the float chamber. Some previous advice was to use a Dremel tool and smooth the insides of the float chamber so the float doesn?t rub or touch. Pretty important.
Set the float so the top of it rests 1 27/32" above the flat surface of the float chamber.
[Note a new float might already be set correctly.]

INITIAL settings are as follows to get the engine started;
Main fuel adjusting screw; big screw facing down at an angle, towards the rear, at the bottom of the carb; 2 1/2 to 3 turns open. This main screw turns clock-wise for leaner mixture. [This screw adjusts fuel.]
Idle-air-mixture screw; smaller screw facing forwards, on upper left-hand side of carb; 1 to 1 1/2 turns open. This idle screw turns counter-clockwise for leaner. [This screw adjusts air.]
Idle speed screw; faces outboard, at the top of the carb; set for 450 rpm, and make sure the governor correctly engages in the slot. [This screw adjusts RPM?s.]

FINAL settings are as follows;
Get the engine warmed up, and idling.
Turn OUT the small idle-air-mixture screw until rough running, then turn in until engine idles smooth. (Mine is set at 1 turn open.)
Rev it up, wide open, warmed up, then turn the big main fuel adjusting screw IN until rough, then out til smooth, then 1/4 turn to 1/2 turn further out. (Mine is set at 1 turn open. Other advice has been to set it at 2 1/2 turns open for pulling implements.)

Engine should rev up smoothly and evenly.
Too Lean = stumble, sputter, damaged melted plugs.
Correct = tan plugs.
Too Rich = back smoke, black sooty plugs.

(quoted from post at 18:59:19 07/15/17) Just had the carb rebuilt. Need to know how to set the air and gas mixture

Click to expand...

The initial factory settings SHOULD have been done by whoever rebuilt it. The settings are in the carb rebuild instructions.

Thanks AGAIN for good advice

I disagree, I can idle my MH44 right at 14.7 fine.

The richer mixture during load is to provide excess hydrocarbons to carry off heat.