There are two fuel adjustments that need attention due to elevation change. The Idle adjustments are near the top of the carburetor. One is near the tube that comes from the governor, about 1/2 inch to the right of the 2 screw flange that holds the tube to the carb. This is the Idle Speed screw and adjusts RPM at idle only, CW is faster and CCW. The second screw is located farther up on the attachment flange that mounts the carb to the manifold. This screw is the mixture screw it controls Idle richness by leaning the mix when screwed outward CCW, and richening when turned inward CW. The second adjustment is high speed load mixture. This single screw is located at the front bottom of the carb pointing with the slotted head toward the radiator. This load screw is adjusted to tailor the fuel mix when the tractor is working. Adjustment: With the tractor running at 2/3 throttle the load screw needs to be turned inwards until the engine begins to change sound, as though too little fuel, then screwed outward 1/4 turn. Now get the tractor warmed up so adjustments are more accurate. When warm,(running for 15 minutes not looking at the temp gauge) adjust this load screw so that if the throttle lever is moved from Idle to full throttle very quickly, that there is no stumble or hesitation. A small amount of darker smoke can be seen at the muffler output as this happens but that should clear up when the engine is at full speed. When working hard plowing or discing, the exhaust should be almost clean of dark grey smoke. This provides a reasonable mixture for work loads, and there should be no hesitation or stumble from idle to Full throttle.
The idle mixture should be adjusted as follows: with the high speed adjustment done, the idle speed screw should be adjusted for a very slow speed, pretty much as slow as it will stay running. Then the mixture screw should be turned in, or out, to make it run as fast as it can without adjusting the idle speed screw. Then readjust the speed screw for a slow idle again and repeat this until it idles smoothly and slow.
Now make sure the load screw adjustment has not changed its effectiveness. These adjustments assume several things, one is good sparkplugs, another is good fuel, a third is the point gap and timing are correct. Manuals (operator and repair) are available here on YT store, they are really critical. I am a super H owner for all but three hears of my life from birth to 1953. Jim
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Today's Featured Article - A Cautionary Tale - by Ian Minshull. In the early 1950s my father bought an Allis Chalmers B and I used it for all the row crop work with the mangolds and potatoes, rolling and the haymaking on our farm. The farm and the Allis were sold and I have spent a lifetime working on farms throughout the country. I promised myself that one day I would own an Allis. That time event
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