Set speed control lever so that throttle valve is open slightly. Make certain that fuel supply to carburetor is open. Close choke valve. Start engine and partially release choke. After engine has been run sufficiently to bring up to operating temperature throughout, see that choke is returned to wide open position.
Advance speed control lever to wide open throttle position which will be fast idle or governor controlled idle. Adjust idle adjusting needle until engine runs evenly.
NOTE: To enrich the idle mixture, turn idle adjusting needle to the left or counter-clockwise.
To secure maximum fuel economy with tractor pulling load, turn the load adjusting needle to the right, or clock-wise, until the power drops appreciably. Then turn the needle to the left, or counter-clockwise, until the engine picks up power and runs smoothly. 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.
If, when load is released, governor closes throttle clear shut, causing uneven running or “hunting,” (governor opening and closing) turn the throttle stop screw against the throttle lever stop spring until the “hunting” is corrected and idling is satisfactory. Normally there is 1/32” clearance between the throttle stop screw and the throttle lever stop spring at fast idle.
To check the float setting, the casting must be held in an inverted position so that the float lever is in contact with the float valve and the float valve seated.
| CARBURETOR MODEL | FACTORY SETTING | WHERE TO MEASURE |
|---|---|---|
| DLTX-26 and 46 | 27/32” | From the bottom of the nozzle boss to the nearest surface of the float. |
| DLTX-67, 71, 72, 73 | 3/8” | From the bowl gasket to the nearest surface of the float. |
| All other DLTX (except duals) (cork or metal float) | 1/2” | From the bowl gasket to the nearest surface of the float |
| Duplex DLTX | 3/4” | From bowl gasket seat in casting to bottom of float |