Exploded views and diagrams (DLTX)
The Marvel Schebler DLTX carb is a horizontal type carburetor used on John Deere tractors. To meet the specific engine requirements of the individual tractor on which the carburetor is installed, requires different size jets, nozzles, venturi, throttle and choke operating levers, etc. For this reason, when ordering parts, always refer to the individual carburetor service parts list for the engine on which the carburetor is installed.
The Model DLTX carburetor consists of two castings:
The throttle body casting contains, in addition to the throttle assembly, a venturi machines in the casting and the choke assembly. Cast iron material is used for ruggedness. All passages, whenever possible, are drilled within the casting to prevent any fuel leaks to the outside of the carburetor because of shrunken gaskets or defective hole plugs.
The model DLTX carb is completely sealed against dust or dirt. All iar entering the fuel bowl of the carburetor must first pass through the air cleaner. The throttle shaft bearings and the choke shaft bearings are sealed to eliminate dust and dirt entering at these points. New throttle shaft bushings can be installed when the bearings have become worn.
The float mechanism is contained in a cast iron fuel bowl on all DLTX models with the exception of the DLTX-26 and DLTX-46 in which the float assembly is retained by the throttle body casting surrounded by a stamped metal fuel bowl.
All models have a fuel strainer to prevent dirt and foreign substance from entering the fuel bowl.
A calibrated economizer plug is used in the back suction economizer system to regulate the air pressure in the fuel bowl chamber for proper fuel delivery to the engine. The size of the plug is carefully established by engineering tests and the specified size for a given carburetor model must always be used to assure the proper operation of the carburetor on the engine. In some models, a calibrated fixed orifice is machined in the throttle body casting in place of the economizer plug.
To provide additional economy, in addition to the back suction economizer system, the carburetor provides for two adjusting needles, the low speed or idle adjusting needle and the load adjusting needle. These needles must not be interchanged. The idle adjusting needle head is brass plated and the load needle cadmium plated (gray color) to distinguish.
A throttle lever stop spring is prodivded to prevent uneven running or “hunting” (governor opening and closing) when the load is released and the governer closes clear shut. 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.
When there are many variations produced by combining the types and sizes into a specific application, all DLTX carburetors incorporate the same engineering principles and are alike from a functional standpoint.