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Marvel Schebler Adjustments

FLOAT LEVEL

TSX float level – 1/4″ measured from the gasket to the nearest surface of the float.

Marvel Schebler Float Level Adjustment
Do NOT put any pressure on the needle when adjusting. It will LEAK.

PRELIMINARY ADJUSTMENTS
Set throttle stop screw so that throttle valve is open slightly, make certain that fuel supply to carburetor is open.
Close choke valve. Start the engine and partially release choke, After the engine has been run sufficiently to bring up to operating temperature throughout, see that choke is returned to wide-open position.


LOW SPEED OR IDLE ADJUSTMENT
Set throttle of governor control lever in the slow idle position and adjust throttle stop screw for the correct engine idle speed. (On a new, stiff engine this speed must be slightly higher than required for a thoroughly run-in engine.)
Turn idle adjusting needle until engine begins to falter or roll from richness, then turn needle in the opposite direction until the engine runs smoothly.
NOTE: It is better that this adjustment be slightly too rich than too learn.


IDLE ADJUSTING NEEDLE—AIR ADJUSTING
To richen the idle mixture, turn the idle adjusting needle to the right or clockwise,


IDLE ADJUSTING NEEDLE —FUEL ADJUSTING
To richer, the idle mixture turns the idle adjusting needle to the left or counterclockwise.


POWER OR LOAD ADJUSTMENT (TYPE B, TYPE C)
With the engine running at governed speed under load, turn power adjusting needle to the right, or clockwise. a little at a time until the power drops appreciably. Then turn the needle to the left, or counterclockwise, until the engine picks up power and runs smoothly, this will give an economical part throttle mixture, and, due to the
economizer action, the proper power mixture for full-throttle operation. Due to variations in temperature or fuels, it may be necessary to richen up this mixture by backing out the power adjusting needle, a small amount at a time until good acceleration is obtained.

NOTE: Carburetor TSX-107, TSX-330, TSX. 339, TSX-355, TSX-385, and TSN-398 use the fuel gas adjusting type
idle needle. All other Model TXN Carburetors use the air adjusting type idle needle.

Updated on 10/01/2021

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